B    3    103 


MONOGRAPH 


OF    THE 


i 

TRILOBITES  OF  NORTH  AMERICA: 


WITH 


of  .tte.  Specter 


THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 

PRESENTED  BY 

PROF.  CHARLES  A.  KOFOID  AND 
MRS.  PRUDENCE  W.  KOFOID 


MONOGRAPH 


TRILOBITES  OF  NORTH  AMERICA 


(Eoiouutr  JHotrels  of  tHe 


Multa  rcnascentur  qu£e  jam  cccidere. — Hon. 


JACOB  GREEN,  M.  D. 

Profjssor  of  Chemistry  in  Jefferson  Medical  College. 


PHILADELPHIA: 

PUBLISHED  BY  JOSEPH  BRAND,  No.  12,  CASTLE  STREET. 
Clark  &  Raser,  Printers. 

1832. 


the  Eastern  District  of  Pennsyl*^™       *"  Dlstrict  Court  <* 


To  JOHN  GEORGE  CHILDREN,  ES^UIUE, 

F.  R.  S.  L.  &  E. 

THE  kindness  which  a  traveller  receives  when  in  a 
distant  land,  must  ever  be  among  his  most  pleasing 
recollections — your  attentions  therefore  to  me,  during 
any  short  residence  in  London  a  few  years  since,  can- 
not easily  be  forgotten.  Suffer  me,  then,  to  inscribe 
this  little  work  to  you  as  a  token  of  my  gratitude. 

Our  pursuits  in  the  Natural  and  Physical  Sciences 
have  been  congenial.  Your  interesting  researches 
with  your  original  and  magnificent  Galvanic  Battery, 
first  drew  my  attention  to  the  calorific  effects  of  that 
mysterious  agent;  and  your  works  on  Natural  His- 
tory have  stimulated  my  exertions  in  the  same  fasci- 
nating pursuit. 

A  large  portion  of  your  time  and  fortune  have  been 
•devoted  to  the  patronage  or  the  cultivation  of  Natu- 
ral Science — so  that  the  dedication  of  this  work  to 
you,  if  it  w-ere  infinitely  more  worthy  of  your  accept- 
ance, would  be  due  from  me,  both  as  a  tribute  of 
liigh  respect,  as  well  as  of  grateful  acknowledgment. 

Philadelphia,  October  1st,  1832, 


ivi36194:l 


EXPLANATION  OF  THE  PLATE. 

Figure  1.  Trimerus  Delphinocephalus. 

2.  Calymene  Diops. 

3.  Asaphus  Micrurus. 

4.  Cryptolithus  Tessellatus. 

5.  Paradoxides  Boltoni. 

6.  Triarthrus  Beckii. 

7.  Isotelus  Cyclops. 

8.  Dipleura  Dekayi. 

9.  Head  of  D.  Dekayi. 

10.  Ceraurus  Pleurexanthemus. 

The  above  figures  represented  on  the  Frontispiece  to  this 
volume,  were  first  published  in  the  Monthly  Journal  of  Geo- 
logy, &c.  for  June,  1832,  and  I  am  indebted  to  C.  A.  Poulson? 
Esq.,  for  the  use  of  them  in  this  Monograph. 


INTRODUCTION, 


SOME  geologists  imagine  that  the  order  of  creation 
is  registered  in  the  rocks  which  compose  the  external 
crust  of  the  earth,  and  that  they  can  there  clearly  read 
a  progressive  development  of  organic  life;  in  other 
words,  that  a  succession  of  more  perfect  animals  may 
be  traced  in  ascending  from  the  lower  strata  to  the 
upper  or  more  recent  formations;  that  there  is  a  gra- 
dual approach  to  the  present  system  of  things,  and  a 
succession  of  destructions  and  creations;  worlds  of 
living  beings  alternating  with  worlds  of  desolation 
and  death,  antecedent  to  the  existence  of  man. 

Others,  again,  contend  that  there  is  often  a  wide 
and  palpable  discrepancy  between  the  nature  of  the 
rock,  and  the  fossils  which  it  contains,  and,  therefore, 
that  such  inquiries  afford  no  clue,  whatever,  to  the 
order  of  creation.*  We  propose  not  to  enter  the  field 

*  Nothing  can  be  more  opposed  to  true  science,  than  to  pro- 
nounce on  the  priority  of  formation,  or  the  comparative  age  of 
rocks,  from  either  their  structure,  or  the  organic  remains  they 
present.  M.  Alexandre  Brongniart  thus  propounds  his  opinion  : 
"  In  those  cases  where  characters  derived  from  the  nature  of  the 
rocks  are  opposed  to  those  which  we  derive  from  organic  re- 
mains, I  should  give  the  preponderance  to  the  latter."  This 
seems  to  us  to  imply  an  admission,  that  nothing  definite  can  be 
inferred  from  the  nature  of  the  rocks;  moreover,  that  between 
A  2 


of  controversy.  Fossils  are  undoubtedly  historic  me- 
dallions of  remote  periods  in  the  natural  history  of 
our  earth,  and  our  design  is,  merely  to  illustrate  with 
them  a  neglected  department  of  ancient  zoology,  by 
describing  a  few  which  have  recently  fallen  under  our 
own  observation. 

In  some  varieties  of  rocks  there  is  often  found  the 
fossil  remains  of  an  animal  which  bears  some  resem- 
blance to  certain  species  of  the  crab.  The  back  of 
this  organic  relic  is  commonly  divided  by  two  deep 
grooves  or  furrows,  into  three  longitudinal  lobes,  and 
from  this  circumstance,  the  term  Trilobite  has  been 
applied  as  a  family  name  to  distinguish  this  whole 
race  of  beings.  This  general  appellation,  however, 
though  in  most  of  the  species,  highly  appropriate,  is 
by  no  means  applicable  to  all. 

The  individuals  which  compose  the  family  of  the 
trilobites  resemble  each  other  in  many  important  par- 

the  nature  of  the  rock,  and  the  organic  remains,  there  may  be  a 
palpable  discrepancy ;  and  that  these  may  be  even  at  complete 
antipodes  with  each  other.  The  event  has  proved,  from  what  we 
have  already  mentioned,  that  no  evidence  as  to  priority  can  be 
obtained  from  the  nature  of  the  fossil  remains  displayed  in  parti- 
cular strata.  In  addition  to  what  has  been  said  on  this  subject, 
we  may  further  state,  that  encrinites,  entrochites,  and  pentacri- 
nites  are  found  in  clay  slate,  grauwacke,  transition  limestone,  al- 
pine limestone,  lias,  muschelkalk,  and  chalk.  It  may  be  reasona- 
bly asked  how  these  three  species  of  fossils  could  indicate  any 
particular  formation,  when  they  are  found  in  so  many  types  and 
structures  of  rocks  altogether  different  ?  If  they  would  go  to 
prove  any  thing  at  all,  it  would  be  that  of  a  contemporaneous  for- 
mation ;  but  certainly  not  distinct  epochas. — See  Eclectic  Review, 
July,  1832. 


ticulars,  and  form  together  an  exceedingly  natural 
group.  The  body,  with  but  few  exceptions,  is  di- 
vided transversely  into  three  parts.  The  anterior 
portion  or  head  often  resembles  the  buckler  of  the 
horse  foot  or  king  crab  (limulus  polyphemus),  so  com- 
mon on  our  sea  coast.  The  middle  portion  is  the  abdo- 
men,  and  is  always  separated  transversely  into  a  num- 
ber of  segments  or  articulations,  generally  diminish- 
ing in  breadth  as  they  recede  from  the  head.  The 
posterior  end  is  the  tail^  which,  though  in  some  spe- 
cies, a  mere  prolongation  of  the  abdomen,  that  can 
scarcely  be  distinguished  from  it,  yet  in  others  it  as- 
sumes a  genuine  caudal  appendage. 

The  head  of  the  trilobite  is  also  generally  divided 
into  three  parts:  the  middle  is  called  the  front,  or  fore- 
head; and  the  lateral  portions  the  cheeks.  In  most 
cases,  a  projecting  tubercle,  or  knob,  is  observable  on 
the  anterior  surface  of  each  cheek,  which  has  much 
the  appearance  of  an  eye.  Its  reticulated  structure 
is  in  many  instances  so  analogous  to  that  of  the  eyes 
of  some  crustaceous  animals,  and  also  of  some  spe- 
cies of  insects,  that  there  can  be  but  little  doubt  that 
these  tubercular  projections,  were  true  organs  of  vi- 
sion. 

Some  of  the  genera  which  belong  to  this  remarka- 
ble race  of  fossil  animals,  possessed  the  power  of 
rolling  or  coiling  themselves  up  into  a  kind  of  ball, 
like  certain  species  of  insects,  or  like  the  armadillo; 
and  they  are  always  found  embedded  in  the  rocks  in 
this  attitude. 

Such   are  the  general  characters  by  which  these 


8 

petrifactions  may  be  known,  and  they  will  be  found 
illustrated  in  a  manner  more  or  less  striking,  in  most 
of  the  species.  The  exceptions,  which  rarely  oc- 
cur, will  be  distinctly  marked,  when  the  species  are 
described. 

The  superior  covering,  or  upper  shell  of  the  trilo- 
bite  is  the  only  part  of  the  animal,  concerning  which 
we  have  any  satisfactory  knowledge.  It  is  conjec- 
tured that  it  was  furnished  with  articulated  feet,  but 
no  traces  of  any  organs  of  progressive  motion  have 
hitherto  been  fairly  discovered.*  Hence,  it  may  be 
reasonably  supposed,  that  the  structure  of  the  lower 
portions  of  the  animal  were  so  soft  and  delicate,  as  to 
render  them  incapable  of  sustaining  the  process  of 
mineralization,  which  the  hard  crustaceous  covering 
of  the  back  so  successfully  undergoes. 

That  these  petrifactions  were  once  marine  animals 
there  can  be  little  doubt,  for  they  are  always  found 
associated  in  the  same  rocks  with  shells,  and  other 
productions  peculiar  to  the  sea. 

The  Trilobite  is  supposed  by  many  naturalists  to 

*  Mr.  Parkinson  states,  that  in  a  trilobite  which  he  possessed  he 
thought  he  perceived  the  points  of  the  feet;  but  on  endeavouring 
to  detach  the  piece  of  rock  in  which  it  was  embedded,  the  speci- 
men was  entirely  shivered,  though  he  worked  at  it  with  the  t\t- 
most  care.  A  portion  of  the  underside  of  a  trilobite  (Isotelus 
gigas)  near  the  anterior  edge  of  the  head,  was  distinctly  ascer- 
tained, by  Dr.  Dekay,  but  only  enough  to  convince  him  of  its 
analogy  in  this  part  with  that  of  the  limulus  polyphemus — no  or- 
gans of  locomotion  could  be  seen.  Mr.  Stokes,  the  distinguished 
fossilist  of  London,  has  confirmed  the  observation  of  Dr.  Dekay, 
by  some  dissections  of  his  own. 


9 

be  one  of  the  first  animated  beings  of  our  earth  call- 
ed into  existence  by  the  great  Author  of  nature.*  It 
was  first  noticed  more  than  two  centuries  ago,  among 
the  petrifactions  which  abound  in  a  calcareous  rock, 
at  Dudley,  in  England,  and  was  from  this  circum- 
stance, called  for  a  long  time,  the  Dudley  fossil. 
Linne  gave  it  the  name  of  the  Paradoxical  insect;  but 
whether  an  insect,  a  crustaceous  animal,  or  a  shell,  is 
still  considered  by  many  as  problematical. 

Notwithstanding  the  high  antiquity  of  the  family 
of  the  Trilobites,  and  the  remarkable  characters  the 
different  individuals  which  compose  it,  sustain  in  the 
animal  kingdom;  till  within  a  very  few  years,  the 
whole  race  has  been  almost  entirely  neglected  by 
naturalists.  The  first  attempt  at  any  systematic  ar- 
rangement of  the  genera  and  species,  was  made  in 
1815,  by  Alexander  Brongniart,  Professor  of  Minera- 
logy, 8cc.  8cc.,  in  Paris. f  Until. that  period,  the  term 

*  It  is  obvious,  that  if  most  of  the  gelatinous  animals  which 
now  inhabit  our  seas,  were  to  become  extinct,  few  or  no  traces 
of  them  could  be  found  in  any  succeeding  depositions  of  earthy 
matter.  Whatever  kind  of  animal  life,  therefore,  may  have  been 
the  first  which  appeared  in  our  planet,  must  be  entirely  hypothe- 
tical. All  that  we  can  with  certainty  say  of  it,  is,  that  it  was 
best  adapted  to  the  circumstances,  in  which  it  was  to  exist,  and 
that  it  was  consistent  with  the  wisdom  and  design  which  we 
see  every  where  pervading  the  universe. 

t  I  cannot  let  this  opportunity  pass,  without  acknowledging 
my  obligations  to  Professor  Brongniart,  for  his  civilities,  when 
on  a  late  visit  to  Paris.  Every  one  whose  curiosity  leads  him 
to  examine  the  royal  manufactory  of  porcelain,  a  Sevres,  of 


10 

Entomolithus  Paradoxus,  proposed  by  Linne,  was  ap- 
plied to  all  the  fossil  remains,  which  in  their  general 
appearance  bore  any  resemblance  to  that  found  at 
Dudley,  and  which  he  first  described  under  that 
name.  The  confusion,  therefore,  which  existed  in 
this  department  of  natural  science,  may  readily  be 
imagined;  especially,  as  the  species  rapidly  multi- 
plied, when  they  were  supposed  to  throw  some  rays 
of  light  on  certain  obscure  geological  phenomena. 
Soon  after  the  appearance  of  Professor  Brongniart's 
excellent  work,  the  attention  of  other  naturalists  was 
directed  to  this  neglected  part  of  creation.  The 
most  important  memoir,  on  account  of  the  number  of 
species,  well  figured  and  described  in  it,  is  one  by 
Dr.  E.  W.  Dalmann,  published  in  the  Transactions  of 
the  Swedish  Academy,  for  1826,  There  is  also  in 
the  Acts  of  the  Royal  Society,  at  Upsal,  an  excellent 
paper  on  this  subject  by  Professor  Wahlenberg. 
Our  highly  esteemed  friend,  Dr.  James  E.  Dekay, 
has  also  given  in  the  first  volume  of  the  Annals  of 
the  Lyceum  of  Natural  History  of  New  York,  some 
very  interesting  and  ingenious  observations  on  the 
nature  and  the  structure  of  the  Trilobites,  with  a  de- 
scription of  a  new  genus.  These  are  the  principal 
authorities  which  have  been  consulted  in  arranging 
the  present  work. 

Our  object  in  the  present  undertaking  being  mere- 
ly to  give  a  monograph  of  the  species  of  Trilobites 

which  he  is  the  director,  will  no  doubt  acknowledge  that  his 
talents  as  a  philosopher,  are  rivalled  by  his  accomplishments  as 
ft  gentleman. 


11 

found  in  the  rocks  of  North  America^  we  leave  to 
other  and  abler  hands  the  more  difficult  and  interest- 
ing task  of  determining  with  precision  the  connex- 
ion which  may  exist  between  these  organic  reliques, 
and  the  relative  ages  of  the  strata  in  which  they  are 
found. 

It  is  supposed,  indeed,  that  a  sufficient  number  of 
well  characterized  species  have  not  yet  been  collected 
and  accurately  described,  to  throw  any  certain  and 
clear  light  on  otherwise  doubtful  geological  pheno- 
mena. What  has  been  remarked  by  De  Candolle, 
with  regard  to  botanical  geography,  is  perhaps  true 
of  these  fossils  as  to  solving  the  difficult  problems  of 
geology — u  Let  us  not  forget,"  says  he,  "  that  this 
science  can  only  be  commenced  when  the  study  of 
species  has  been  sufficiently  advanced  to  furnish  us 
with  numerous  and  well  authenticated  facts." 

We  are  well  aware  of  the  difficulty  of  settling  the 
line  which  ought  to  divide  species.  Individuals  per- 
fectly identical  in  all  their  parts,  are  rarely,  if  ever 
seen;  though  a  general  resemblance  may  be  easily 
traced.  Among  fossils,  just  discriminations  of  this 
kind  are  more  delicate,  than  in  recent  specimens. 
The  hand  of  time,  accidental  causes,  and  the  influ- 
ence of  atmospheric  changes  often  produce  such 
characters  as  to  render  the  determination  of  fossil 
species  an  exceedingly  difficult  task.  We  have  no 
doubt,  therefore,  that  a  few  of  our  Trilobites,  which 
are  now  considered  as  perfectly  identical  with  some 
found  in  Europe,  will  upon  fuller  examination,  be 
discovered  to  be  dissimilar,  and  of  course  certain 


12 

geological  speculations  grounded  on  the  first  opinion, 
be  ultimately  abandoned. 

The  geographical  distribution  of  organic  remains, 
is  an  exceedingly  curious  inquiry.  If  accurately  pur- 
sued, without  reference  to  any  preconceived  theory, 
it  will  no  doubt  furnish  much  information  as  to  the 
comparative  ages  of  the  different  strata  which  com- 
pose the  external  crust  of  our  planet — for  that 
these  strata  were  deposited  or  formed  at  periods  of 
time  more  or  less  remote  from  each  other,  every  one 
knows,  to  be  a  generally  admitted  geological  fact. 
The  occurrence  of  similar  fossils  in  districts  of  coun- 
try remotely  situated  from  each  other,  certainly  pre- 
sents a  phenomenon  highly  interesting  to  the  specu- 
lative naturalist,  and  apparently  indicates  that  the 
same  powerful  and  general  causes  must  have  con- 
curred to  produce  these  isomorphous  depositions. 
No  fossils  have  contributed  more  to  this  kind  of  in- 
formation, than  those  of  shells,  and  as  the  mineralized 
species  could  not  be  satisfactorily  studied,  except  by 
accurately  comparing  them  with  those  which  now 
inhabit  our  seas  and  continents;  the  search  for  shells, 
has  become,  from  a  simple  amusement,  the  study  of 
scientific  men — or,  as  a  writer  remarks,  "  it  was  only 
after  the  period  when  it  was  perceived  that  geology 
and  ancient  zoology  were  destined  to  be  enlightened 
by  their  fossil  remains,  that  this  research  passed  from 
the  hands  of  amateurs  into  those  of  naturalists."* 

*  We  have  not  unfrequently  noticed,  both  in  the  writings  and 
conversation  of  some  geologists,  a  disposition  to  sneer  at  the 
subsidiary  branches  of  natural  history.  Mineralogy  and  con- 


13 

Another  curious  geological  fact  appears  to  be  esta- 
blished more  especially  by  fossil  trilobitesj  it  is  that 
precisely  the  same  species  of  animal  relic,  is  the 
most  generally  diffused  over  the  globe,  in  proportion 
to  the*antiquity  of  the  rock  which  contains  it.  Thus 
the  transition  limestone  of  England,  France,  Ger- 
many and  Sweden,  contains  the  species  called  the 
Calymene  of  Blumenbach,  in  common  with  the  same 
formation  which  extends  over  so  large  a  portion  of 
the  United  States. 

Different  genera  and  species  of  the  trilobite  are 
now  found  in  almost  every  part  of  the  globe,  and  are 
frequently  exceedingly  abundant  in  the  rocks  which 
contain  them.  That  they  must  have  swarmed  in 
particular  places,  is  abundantly  evident  from  a  num- 
ber of  localities  in  our  own  country, — millions,  for 
example,  must  have  lived  and  died  not  far  from 
Trenton  falls,  in  the  State  of  New  York.  There  are 
very  few  of  the  numerous  visiters  to  that  romantic 
cascade,  whose  curiosity  is  not  awaked,  by  the  multi- 
tude of  these  petrified  beings,  seemingly  of  another 
world,  which  are  there  entombed. 

chology,  are  light  and  mean  in  their  estimation,  when  compared 
with  the  study  of  extensive  strata  and  ponderous  boulders.  Like 
Irving's  testy  governor  of  Manahatta,  who  settled  the  accounts  of 
his  clients  by  placing  their  books  in  the  opposite  scales  of  a  ba- 
lance, they  decide  on  the  value  of  a  science,  by  the  absolute 
weight  of  the  objects  embraced  by  it.  Geology,  as  well  as  any 
other  branch  of  natural  history,  may  degenerate  into  a  mere  love 
for  the  curious,  or  have  for  its  principal  aim,  the  perfection  or 
improvement  of  some  ideal  system  of  classification,  without  ad- 
vancing a  single  step  further. 


14 

Although  many  parts  of  the  trilobite  are  now  found 
distributed  through  the  rocks  which  contain  them, 
in  such  a  manner  as  to  lead  to  the  conclusion,  that 
they  were  separated  by  decomposition,  after  the 
death  of  the  animal;  yet  the  perfect  preservation  of 
others,  and  the  rolled  and  disjointed  attitudes  which 
we  should  expect  such  creatures  to  assume  when 
disturbed,  lead  to  the  conjecture,  that  they  have  been 
often  suddenly  destroyed,  and  as  suddenly  enveloped 
in  that  earthy  matter,  which  afterwards  became  an 
indurated  rock;  thus  preventing  the  separation  of 
the  harder  parts,  by  the  slow  process  of  decom- 
position.* 

The  fossil  remains  of  the  trilobite  family,  are  sup- 
posed by  most  naturalists  to  belong  to  a  race  of  beings 
now  extinct;  but  from  the  strong  analogy  which  ex- 
ists between  them  and  certain  species  of  crustaceous 
animals  now  living,  it  is  highly  probable  that  they 
will  yet  be  found  alive.  This  opinion  will  not  be 
regarded  as  visionary,  when  it  is  recollected  how 
large  a  portion  of  the  surface  of  the  earth  is  still  un- 
explored by  its  enlightened  and  civilized  inhabitants 
—how  small  the  number  of  animated  beings  are  yet 
known  to  the  scientific  world— and  above  all  the  fact, 
that  many  animals  as  confidently  declared  to  be  pecu- 
liar to  a  former  world,  are  now  found  to  be  among 
the  creatures  at  present  in  existence.  This  opinion, 
we  think,  is  quite  as  plausible,  and  far  more  interest- 
ing, than  the  blank  and  unsatisfactory  hypothesis  that 

*  Vide  De  la  Beche's  Geological  Manual. 


15 

all  the  trilobites  are  confined  to  an  order  of  things 
before  the  present  glorious  creation.* 

There  appears  to  have  been  known  to  naturalists, 
when  the  improved  edition  of  Prof.  Brongniart's  work 
on  the  trilobites  appeared  in  1822,  but  17  well  mark- 
ed species,  and  out  of  which  he  constructed  the  five 
following  genera,  which  he  thus  characterizes, 

Genus  First.     CALYMENE. 

Body  capable  of  contraction  into  nearly  a  semi- 
cylindrical  sphere. 

Buckler  with  many  tubercles  or  folds.  Two  reticu- 
lated eye-shaped  tubercles. 

Jlbdomen  and  Post-abdomen  with  entire  edges.  Ab- 
domen divided  by  12  or  14  articulations. 

No  elongated  tail. 

*  The  incorrectness  of  the  inference  that  all  the  genera  and 
species  of  fossil  animals  found  in  the  transition  rocks  must  be 
now  extinct,  will  appear  from  the  following  extract  from  Bake- 
well's  Geology: — "  The  Madrcpora  stylina,  so  common  in  transi- 
tion lime-stone  rock,  is  entirely  wanting  in  the  secondary  and 
tertiary  strata,  but  a  living  animal  of  this  species  has  been  recent- 
ly discovered  in  the  South  Seas.  The  Pentacrinus  makes  its  first 
distinct  appearance  in  the  lias;  but  is  not  frequently  met  with 
in  the  upper  strata,  and  disappears  entirely  in  the  uppermost  for- 
mations :  hence  it  was  long  supposed  that  the  species  was  ex- 
tinct. A  living  Pentacrinus  has  recently  been  discovered  in  the 
West  Indies,  and  its  stem  and  branches  in  a  perfect  state  have 
been  sent  to  this  country."  (England.)  In  the  Museum  at  Alba- 
ny, N.  Y.,  I  have  examined  a  recent  Pentacrinus,  which  I  con- 
clude, came  from  the  West  Indies,  from  the  proprietor's  account 
of  the  manner  in  which  he  obtained  it.  It  has  been  a  very 
perfect  specimen — but  the  branches  are  gradually  dropping  off." 


16 

Genus  Second.     ASAPHUS. 

Body  broad  and  rather  flat.  Middle  lobe  promi- 
nent and  very  distinct. 

Flanks  or  lateral  lobes  each  double  the  size  of  the 
middle  lobe. 

Submembranaceous  expansions  extending  beyond  the 
lateral  lobes. 

Buckler  semicircular,  with  two  reticulated  eye- 
shaped  tubercles. 

Abdomen  divided  into  8  or  12  articulations. 

Genus  Third.     OGYGIA. 

Body  much  depressed  into  an  oblong  ellipsis — not 
contractile  into  a  sphere. 

Buckler  edged,  a  slight  longitudinal  furrow  aris- 
ing from  its  anterior  extremity.  Posterior  angles 
elongated  into  points. 

Without  any  tubercles  except  the  eyes,  which  are 
neither  prominent  nor  reticulated. 

Longitudinal  lobes  slightly  prominent. 

Abdomen  with  8  articulations. 

Genus  Fourth.     PARADOXIDES. 

Body  depressed — not  contractile. 

Flanks  much  broader  than  the  middle  lobe. 

Buckler  nearly  semicircular — three  transverse  fur- 
rows on  the  middle  lobe. 

Eye-shaped  tubercles  none. 

Abdomen  with  12  articulations. 

Arches  of  the  lateral  lobes,  more  or  less  prolonged 
beyond  the  membrane  which  sustains  them. 


17 

Genus  Fifth.     AGNOSTUS. 

Body  ellipsoidal — semicylindrical. 

Buckler  and  flanks  edged — the  edges  being  slightly 
elevated. 

Middle  lobe  with  two  transverse  divisions,  each  com- 
posed of  a  single  piece. 

Two  glandular  tubercles  on  the  anterior  part  of  the 
body. 

In  1824,  Dr.  J.  E.  Bekay  added  a  sixth  genus  to 
the  family  of  the  trilobites,  which  he  describes  in  the 
following  manner. 

Genus  Sixth.     ISOTELUS, 

Body  oval  oblong,  often  contracted,  not  unfrequent- 
ly  extended. 

Head  or  buckler  large  and  rounded,  equalling  the 
tail  in  size,  with  but  two  oculiform  tubercles. 

Abdomen  with  8  articulations. 

Frontal  process  beneath,  with  two  semilunar  ter- 
minations. 

Post-abdomen  or  tail  broad,  expanded  with  indis- 
tinct divisions,  as  large  as  the  buckler. 

Longitudinal  lobes  very  distinct. 

This  genus,  he  remarks,  will  be  sufficiently  distin- 
guished from  the  five  genera  proposed  by  M.  Jllexan- 
dre  Brongniart  in  his  valuable  and  truly  philoso- 
phical work  on  the  trilobites  by  the  following  parti- 
culars. 

From  Calymene.  By  the  presence  of  but  two  tu- 
B  2 


18 

bercles  on  the  buckler  not  reticulated;  by  the  abdo- 
men with  but  8  articulations. 

From  Jlsaphm.  By  the  middle  lobe,  which  is  double 
the  size  of  the  lateral  ones;  by  the  absence  of  a  mem- 
branaceous  expansion  on  the  sides;  by  the  non-reticu- 
lation of  the  eyes,  Sec. 

From  Ogygia.  By  the  rolled  form,  the  rounded 
posterior  angles  of  the  buckler,  and  the  distinct  arti- 
culation of  the  longitudinal  lobes. 

From  Paradoxide  and  tfgnoste  by  characters  too 
obvious  to  be  enumerated.  (See  Annals  of  N.  York 
Lyceum,  Sec.  Vol.  I.  pp.  174-5.) 

In  1826,  J.  W.  Dalman  published  in  the  Transac- 
tions of  the  Swedish  Academy,  and  also  in  a  separate 
work,  an  account  of  the  trilobites  found  in  the  North 
of  Europe,  in  which  he  has  enriched  the  family  by  a 
number  of  fine  species,  and  with  the  following  genera, 
which  he  modestly  proposes  merely  as  subdivisions. 

Genus  Seventh.     NILEUS. 

Body  short,  capable  of  contraction  into  a  sphere, 
smooth,  convex. 

Mdomen  with  about  8  articulations,  without  any 
dorsal  longitudinal  furrows. 

Buckler  sub-lunate,  with  large  lateral  eyes. 

Tail  expanded,  not  so  large  as  the  buckler,  without 
lobes. 

Genus  Eighth.     ILLJENUS. 
Body  ovate  oblong,  contractile. 


19 

Head  rounded  in  front,  eyes  small,  in  the  temples, 
very  remote. 

Abdomen  with  from  9  to  10  articulations,  trilobate. 
Tail  expanded  as  large  as  the  head.* 

Genus  Ninth.     AMPYX. 

Body  very  short,  contractile. 

J3uckler  large,  triangular,  gibbous;  eyes  not  re- 
markable. 

Jlbdomen  short,  articulations  few  (6  ?),  trilobate. 

Tail  expanded,  not  so  large  as  the  head. 

Professor  Dalman  has  two  other  genera,  which  he 
calls  Olenus  and  Battus,  the  first  is  the  Paradoxides, 
and  the  second  the  Agnostus  of  Brongniart. 

In  the  8th  Volume  of  Annales  des  Sciences  Natu- 
relles  there  is  a  highly  valuable  paper  "  Sur  les  Tri- 
lobites  et  leurs  gisemens,"  by  the  Count  Rasoumow- 
sky,  in  which  he  describes  some  new  trilobites  from 
Russia;  the  one  which  he  has  figured  and  described 
as  a  Calymenef  from  Tzarsko-Selo,  undoubtedly  be- 
longs to  a  new  genus,  very  near  to  the  Isotelus.  The 
middle  lobe  is  visible  or  naked  through  its  whole  ex- 
tent, and  the  lateral  lobes  near  the  tail  are  covered 
with  a  thick  cuticular  membrane.  This  genus  we 
propose  to  call  Hemicrupturus,  and  may  be  thus  cha- 
racterized. 

*  Some  of  the  species  described  by  Professor  Dalman  as  in- 
cluded in  this  genus,  we  think  ought  to  be  referred  to  that  of  the 
Isotelus. 

t  The  editors  of  the  Annales  remark  that  this  is  not  a  Caly- 
mene.  but  that  it  appears  to  belong  to  the  genus  Asaphus. 


Genus  Tenth.     HEMICRUPTURUS.* — Grem. 

Rody  contractile. 

Buckler  oculiferous  and  not  lobate. 

Abdomen  trilobate,  with  8  articulations. 

Tail,  costal  arches  covered,  middle  lobe  naked. 

The  asaphus  expansus  of  Dal  man,  and  several 
other  known  species  may  be  arranged  under  this 
genus. 

As  Count  Rasoumowsky  has  given  no  specific  ap- 
pellation to  the  fossil  above  alluded  to,  we  propose  to 
call  it  after  his  own  name,  Hemicrupturus  Rasoumow- 
skiL  We  examined  the  fine  specimen  from  which 
our  cast  is  taken  in  the  cabinet  of  the  Baltimore  Col- 
lege, and  for  this  favour  we  are  indebted  to  the  kind- 
ness of  Dr.  J.  J.  Cohen,  one  of  the  Professors  in  that 
rising  institution. 

The  following  list  includes  all  the  genera  and  spe- 
cies of  the  Trilobite  Family,  hitherto  described  as 
far  as  known  to  the  author.  It  is  taken  from  De 
La  Beche's  Manual  of  Geology. 


NAMES. 

Calymene  Blumenbachii, 
Macrophthalma, 
Variolaris, 
Tristani, 
Bellatula, 
Ornata, 
Verrucosa, 


AUTHORS. 

LOCALITIES. 

Al.  Brong. 

Europe  —  U.  States. 

do. 

Europe—  U.  States. 

do. 

Europe. 

do. 

Europe—  U.  States. 

Dalman. 

Europe. 

do. 

Europe. 

do. 

Europe. 

From  three  Greek  words  which  signify  half-concealed  tail. 


NAMES. 

AUTHORS. 

LOCALITIES. 

Calymene  Polytoma, 

Dalman. 

Europe. 

Artinura, 

do. 

Europe. 

Sclerops, 

do. 

Europe. 

Schlotheirni, 

Brown. 

Europe. 

Latiferus, 

do. 

Europe. 

Asaphns    Coi'nigerus, 

Al.  Brong. 

Europe. 

Caudatus, 

do. 

Europe  —  U. 

States. 

Hausmanni, 

do. 

Europe  —  U. 

States. 

De  Buchii, 

do. 

Europe. 

Brongniartii, 

Deslongchamps. 

Europe. 

Extenuatus, 

Wahlenberg. 

Europe. 

Granulatus, 

do. 

Europe. 

Expansus, 

do. 

Europe. 

.     Crassicauda, 

do. 

Europe. 

Angustifrons, 

do. 

Europe. 

Heros, 

Dalman, 

Europe. 

Platynotus, 

do. 

Europe. 

Frontalis, 

do. 

Europe. 

Lseviceps, 

do. 

Europe. 

Palpebrosus, 

do. 

Europe. 

Sluzeri, 

Europe. 

Ogygia     Guettardii, 

Al.  Brong. 

Europe. 

Desrnaresti, 

do. 

Europe. 

Wahlenbergii, 

do. 

Europe. 

Sillimani, 

do. 

Europe  —  U. 

States. 

Paradoxides  Tessini, 

do. 

Europe. 

Spinulosus, 

do. 

Europe. 

Gibbosus, 

do. 

Europe. 

Scaraboides, 

do. 

Europe. 

Hoffii, 

Goldf'uss. 

Europe. 

Nilevis        Armadillo, 

Dalman. 

Europe. 

Glornerinus, 

do. 

Europe. 

22 


NAMES. 

Illsenus  Centaurus, 
Centrotus, 
Laticauda 

Ampyx      Nasutus, 
Olenus      Bucephalus, 
Agnostus  Pisciformis, 
Isotelus     Gigas, 
Planus, 


AUTHORS. 

LOCALITIES. 

D  aim  an. 

Europe. 

do. 

Europe. 

Wahlenberg. 

Europe  —  U.  States. 

Dalman. 

Europe. 

Wahlenberg. 

Europe. 

Al.  Brong. 

Europe. 

De  Kay. 

United  States. 

do. 

United  States. 

Genera  and  Species  not  fully  determined. 


Trilobites  Cephaleurya, 
Simla, 
Granulata, 

Bilobites  Lunulata, 
Lobata, 


Rafinesque, 
do. 
do. 
do. 
do. 


United  States. 
United  States. 
United  States. 
United  States. 
United  States. 


From  the  short  descriptions  given  by  Professor 
Rafinesque  of  the  five  last  mentioned  fossils,  I  con- 
clude that  they  belong  to  the  genus  Calymene  of 
Brongniart. 

The  study  of  the  trilobites  naturally  leads  to  the 
consideration  of  those  beings  which  appear  to  have 
inhabited  our  earth  previous  to  the  creation  of  man. 
Every  one  knows  that  the  sceptical  naturalist  has 
drawn  from  these  vestiges  of  organic  life,  an  argu- 
ment contradictory  to  the  Mosaic  account  of  the  his- 
tory of  the  world,  and  though  every  cavil  of  the  least 
importance,  urged  against  the  truth  of  the  sacred 
historian,  has  been  triumphantly  confuted,  still,  the 
geological  sciolist  boldly  impugns  his  veracity,  when- 
ever any  new  facts  in  his  science  can  be  distorted  to 


23 

his  purpose.  Such  being  the  case,  we  cannot  con- 
clude this  preface  without  briefly  stating  two  or 
three  methods  by  which  any  seeming  discrepancies 
may  be  explained.  First,  those  who  imagine  that 
the  six  periods  of  creation,  mentioned  in  the  begin- 
ning of  the  pentateuch,  mean  literally  days  of  24 
hours  each,  believe  that,  as  only  a  small  part  of  the 
earth  was  at  first  required  for  the  abode  of  man  and 
the  higher  animals,  the  present  continents  might 
have  remained  as  long  beneath  the  waters,  and  have 
undergone  every  change  necessary  to  solve  this  geo- 
logical puzzle. 

Again,  others  have  thought  that  Moses,  after  re- 
cording, in  the  first  sentence  of  Genesis,  the  great 
truth  that  all  things  were  made  by  the  will  of  an  in- 
telligent Creator — passed  silently  over  some  interme- 
diate state  of  the  earth,  which  had  no  direct  relation 
to  the  history,  or  to  the  duties  of  man — and  proceed- 
ed to  describe  the  successive  appearance  of  the  pre- 
sent order  of  things.  On  this  supposition,  the  fossil 
remains  and  peculiarities  in  the  structure  of  the 
earth  may  have  belonged  to  that  intermediate  state. 

A  third  method  of  explaining  the  difficulty,  and 
which  we  think  highly  satisfactory,  is,  by  under- 
standing the  days  of  creation  to  mean,  not  ordinary 
days,  but  periods  of  time,  in  which  the  recorded  events 
took  place  in  the  order  described  so  briefly  by  the 
sacred  historian.  It  is  acknowledged  by  every  one 
competent  to  judge,  that  among  the  Hebrews,  days 
and  weeks  were  often  used  in  this  manner.  The  ac- 
cordance between  the  order  in  which,  according  to 


24 

the  account  of  Moses,  the  work  of  creation  was  ac- 
complished, and  the  order  in  which  the  fossil  re- 
mains of  plants  and  animals  are  deposited  in  the 
earth,  has  surprised,  and  has  been  acknowledged  by 
learned  sceptics  themselves.* 

It  will  be  useless  to  push  these  arguments  further. 
The  catastrophes  which  have  produced  the  seconda- 
ry strata,  and  the  diluvian  depositions,  could  not 
have  been  local  or  partial  phenomena;  but  rather 
than  call  upon  a  comet,  with  the  abstracted  philoso- 
pher, to  deluge  the  earth  for  every  new  geological 
epoch — -or  to  change  the  axis  of  motion  of  our  planet 
— or  to  resort  to  any  of  his  wild,  fanciful,  and  impious 
theories,  we  should,  with  Sir  Humphrey  Davy,  even 
prefer  the  dream  that  all  the  secondary  strata  were 
created^  filled  with  the  remains,  as  it  were,  of  animal 
life,  to  confound  the  speculations  of  our  geological 
reasoners. 

*  The  Baron  Cuvier,  on  this  subject,  remarks,  respecting  the 
Jewish  legislator — "His  books  show  us, that  he  had  very  perfect 
ideas  respecting  several  of  the  highest  questions  of  natural  philo- 
sophy. His  cosmogony,  especially,  considered  purely  in  a  scien- 
tific point  of  view,  is  extremely  remarkable,  inasmuch  as  the 
order  which  it  assigns  to  the  different  epochs  of  creation,  is  pre- 
cisely the  same  as  that  which  has  been  deduced  from  geological 
considerations." 


25 


ACKNOWLEDGMENTS. 

Every  author  who  attempts  a  Monograph  of  any 
of  the  departments  of  Natural  History,  must  neces- 
sarily depend,  in  a  greater  or  less  degree,  upon  the 
kindness  and  liberality  of  others.  Rare  and  unique 
specimens,  particularly  of  fossil  species,  are  often 
scattered  through  different  cabinets,  and  his  work 
would  be  rendered  very  imperfect,  if  they  were  not 
intrusted  to  his  care.  In  preparing  the  following 
Monograph  on  the  plan  of  giving  exact  models  of 
the  species,  instead  of  illustrating  them  by  engrav- 
ings in  the  usual  manner,  the  specimens  when  used 
by  the  artist  are  perhaps  more  liable  to  accident,  and 
it  was  at  first  supposed  that  this  circumstance  might 
have  prevented  the  original  design.  But  in  no  in- 
stance, where  an  application  has  been  made,  either  to 
a  public  institution  or  to  a  private  cabinet,  has  the  au- 
thor met  with  a  refusal;  indeed  the  courtesy,  kind- 
ness, and  liberality  which  he  has  experienced  from 
naturalists,  who  have  every  where  aided  him  in  the 
prosecution  of  his  work,  form  no  inconsiderable 
portion  of  the  gratification  which  he  has  received. 
Besides  the  acknowledgments  to  public  museums, 
and  to  individuals,  which  are  made  in  the  body  of 
the  work,  the  author  is  desirous  of  recording  in  this 
place,  the  following  cabinets  from  which  he  has  de- 
rived much  assistance. 

IN  PHILADELPHIA. 

The  Cabinet  of  JOHN  P.  WETHERILL. 

The  Cabinet  of  the  ACADEMY  OF  NATURAL  SCIENCES. 


26 

The  Philadelphia  Museum. — (PEALE'S.) 

The  Cabinet  of  P.  A.  BROWNE,  Esq. 

The  Cabinet  of  DR.  R.  HARLAN. 

The  Cabinet  of  WILLIAM  HYDE. 

The  Cabinet  of  J.  PIERCE. 

The  Cabinet  of  the  GEOLOGICAL  SOCIETY. 

LAMBDIN'S  Museum,  Pittsburgh,  Pa. 
The  Cabinet  of  D.  KEIM,  Reading,  Pa. 

IN  NEW  YORK. 

The  Cabinet  of  the  LYCEUM  OF  NATURAL  HISTORY. 
The  Cabinet  of  DR.  J.  E.  DEKAT. 
The  New  York  Museum. — (PEALE'S.) 

IN  ALBANY. 

The  Cabinet  of  the  ALBANY  INSTITUTE. 
The  Cabinet  of  PROFESSOR  T.  R.  BECK. 
Albany  Museum. 
The  Cabinet  of  DR.  JAMES  EIGHTS. 

The  Cabinet  of  the  RENSSELAER  SCHOOL. 

IN  BALTIMORE. 

The  Cabinet  of  DR.  JOSHUA  J.  COHEN. 
The  Cabinet  of  the  BALTIMORE  COLLEGE. 
The  Cabinet  of  the  ATHENEUM. 
The  Baltimore  Museum. 

The  Cabinet  of  PROFESSOR  HALL,  MOUNT  HOPK. 


TRILOBITES,  dze. 


GENUS  CALYMENE.     Brongniart. 

THE  name  of  this  genus  is  derived  from  a  Greek 
word  which  signifies  obscure  or  concealed.  The  fossil 
animals  included  by  it  are  characterized  as  having 
contractile  bodies;  the  buckler  as  bearing  many  tu- 
bercles or  folds  —  the  cheeks  as  being  oculiferous, 
and  the  abdomen  and  tail  as  being  composed  of  from 
twelve  to  fourteen  articulations  or  joints,  without 
any  membranaceous  expansion.  The  Calymenes  in 
thickness  are  nearly  semicylindrical,  and  the  buck- 
ler in  front  presents  a  chaperon  or  upper  lip  more  or 
Jess  raised.  In  perfect  specimens,  there  is  a  small 
furrow  which  seems  to  indicate  a  separation  between 
the  upper  and  under  parts  of  this  kind  of  lip.  The 
eyes  are  always  raised,  and  frequently  present  the  re- 
markable structure  observable  in  many  of  the  Crusta- 
cea; but  as  this  part  is  generally  very  prominent,  the 
reticulations  of  the  eye  are  commonly  worn  off  or  in- 
jured. 

Professor  Brongniart  places  but  little  confidence 
in  any  of  the  generic  characters  above  enumerated, 
except  the  number  of  articulations  of  the  abdomen: 


28 

these,  however,  in  our  opinion,  are  more  vague  and 
uncertain  than  most  of  the  others.  The  genus,  how- 
ever, we  think  may  be  readily  identified,  after  becom- 
ing- familiar  with  one  well  characterized  species. 
The  general  aspect  of  the  buckler  is  peculiar — the 
body  is  not  so  depressed  as  in  most  other  genera,  and 
the  lateral  lobes  are  destitute  of  all  membranaceous 
expansion. 

To  the  genus  Calymene,  belongs  the  celebrated 
Dudley  fossil,  called  Entomolithus  paradoxus  by  Blu- 
menbach,  but  which  is  not  the  same  organic  relic, 
to  which  Linne  applied  that  name. 

This  genus  includes  a  great  number  of  species,  and 
though  some  of  them  are  said  to  be  found  in  different 
and  distant  parts  of  the  globe,  they  are  according  to 
our  limited  observation,  for  the  most  part  confined, 
like  recent  species  of  animals,  to  particular  districts. 
The  C.  polytoma,  C.  pulchella,  C.  bellatula,  C.  con- 
cinna,  C.  sclerops,  and  the  C.  punctata,  all  finely 
figured  by  Professor  Dalman,  and  which  are  found 
in  Sweden,  have  not  yet  been  noticed  in  any  part  of 
North  America.* 

CALYMENE  BLUMENBACHII.     Brongniart.     Cast  No.  1. 

Clypeo  rotundato,  tuberculis  sex  distinctis  in 
ironte;  oculis  in  genis  emintissimis;  corpore  tuber- 
culato. 

*  See  the  valuable  and  extensive  communication  of  J.  W. 
Dalman,  M.  D  ,  on  the  Trilobites,  in  the  Transactions  of  the- 
Swedish  Academy  for  1820,  part  2d.  - 


29 

In  this  species  the  upper  lip  presents  a  furrow  pa- 
rallel to  its  edges.  The  lip  is  straight.  The  cheeks  are 
a  little  projecting.  There  are  six  rounded  tubercles 
on  the  front,  and  fourteen  articulations  on  the  back; 
the  tail  is  small,  and  the  shell  is  covered  with  small 
rounded  tubercles  of  unequal  sizes. 

The  above  is  Professor  Brongniart's  description  of 
this  trilobite,  which  is  the  famous  Dudley  fossil  de- 
scribed and  figured  by  Littleton,  in  the  Philosophical 
Transactions,  (London)  in  1750.  According  to  Dai- 
man,  several  distinct  European  species  have  been 
published  under  this  name.  The  true  C.  Blumen- 
bachii,  he  says,  has  thirteen  articulations  to  the  abdo- 
men, and  about  eight  to  the  tail.  In  -he  cabinet  of 
G.  W.  Featherstonhaugh,  Esq.,  we  have  examined  a 
fine  perfect  specimen  from  Dudley,*  in  which  there 
is  fourteen  abdominal  joints.  There  can  be  no  doubt, 
however,  that  several  species  have  been  confounded 
under  the  name  of  C.  Blumenbachii;  Dalman's  C, 
Tuberculata  and  C.  Pulchella  are,  we  think,  distinct 
from  it,  though  he  has  marked  them  only  as  varieties. 

The  true  C.  Blumenbachii,  no  doubt,  abounds  in 
North  America,  and  is  one  of  the  few  examples  of  the 
occurrence  of  an  identical  species  on  both  continents. 
The  late  Abbe  Correa  sent  a  perfect  specimen  to 
Brongniart,  from  the  vicinity  of  Lebanon,  in  the  state 

>  This  famous  trilobite,  once  formed  a  part  of  the  cabinet  of 
Mr.  Parkinson,  the  distinguished  author  of  the  "  Organic  Re- 
mains," and  is  accurately  figured  on  one  of  the  plates  of  that 
splendid  work.  At  the  sale  of  the  late  Mr.  Parkinson's  fossils, 
it  was  purchased  by  Mr.  Featherstonhaugh, 


30 

of  Ohio.  We  have  also  seen  a  number  of  specimens 
from  that  state,  which  could  not  be  distinguished 
from  the  Dudley  trilobite.  Our  model  was  taken 
from  a  specimen  found  at  Trenton  Falls,  in  the  state 
of  New  York. 

The  three  following  species  found  in  the  United 
States,  will  no  doubt  be  considered  by  many  as  mere 
varieties  of  the  C.  Blumenbachii;  we  have  ventured, 
however,  to  call  them  by  distinct  names. 

CALYMENE  CALLICEPHALA.*     Green.     Cast  No.  2. 

Clypeo  antice  attenuato,  figura  liliiformi  in  fronte 
depictaj  oculis  minimis;  abdomine  quatuordecim  ar- 
ticulis;  corpore  piano. 

The  buckler  is  subtriangular;  on  the  front  there  is 
a  figure  in  high  relief,  somewhat  resembling  a  fleur 
de  liSj  or  perhaps  more,  the  capital  of  a  Corinthian 
column.  The  oculiferous  tubercles  are  rather  lower 
down  on  the  cheeks  than  usual.  The  articulations 
of  the  abdomen  and  the  tail  cannot  well  be  distin- 
guished from  each,  other;  fourteen  in  all  may  be 
easily  counted.  The  middle  lobe  of  the  abdomen  is 
nearly  equal  in  breadth  throughout.  The  ribs,  or 
costal  arches,  are  not  grooved  or  bifurcated  at  their 
extremities.  Length  nearly  two  inches  and  a  half. 

This  beautiful  species  is  in  the  Philadelphia  Mu- 
seum, where  it  is  labelled  as  being  found  in  "  Hamp- 
shire, Virginia."  It  is  mineralized  by  a  dark  yellow- 

From  two  Greek  words,  which  signify  "  beautiful  head." 


31 

ish  limestone.  It  differs  from  the  C.  Blumenbachil, 
in  the  form  and  number  of  its  articulations;  in  the 
shape  of  the  head;  in  having  only  two  flat  tubercu- 
lous elevations  on  the  front;  and  in  other  particulars. 
In  the  cabinet  of  the  New  York  Lyceum,  and  in 
that  of  J.  P.  Wetherill,  Esq.  there  are  some  examples 
of  this  species  from  the  Miami  river,  near  Cincinna- 
ti, Ohio.  I  have  also  seen  it  from  Indiana,  in  a  dark 
coloured  limestone,  very  much  distorted.  It  has 
never  been  found  at  Trenton  falls,  or  at  any  other  lo- 
cality, as  far  as  my  knowledge  extends,  which  yields 
the  true  C.  Blumenbachii. 

CALYMENE  SELENECEPHALA.*     Green.     Cast  No.  3, 

Clypeo  antice  rotundato,  margine  omni  valde  in- 
crassato;  prominentia  frontal!  utrinque  trituberosa; 
corpore  tuberculato. 

The  buckler  is  regularly  lunate;  the  margin  is 
slightly  reflected  or  raised  anteriorly,  the  posterior 
edge  forms  a  continuous  rim,  running  nearly  parallel 
with  the  articulations  of  the  abdomen.  The  front  on 
each  side  has  one  large  and  two  small  tubercles,  near 
its  superior  edge.  The  oculiferous  tubercles  on  the 
cheeks  are  on  a  line  with  the  lowest  frontal  tubercle. 
There  are  fourteen  distinct  articulations;  but  as  the 
tail  is  mutilated  and  distorted,  the  total  number  of 
joints  cannot,  from  this  specimen,  be  ascertained. 
The  body  appears  to  have  been  covered  with  small 

*  From  the  Greek  for  "  lunate  head." 


32 

pustules,  These  are  very  evident  on  the  front.  Cos* 
tal  arches  simple,  or  not  grooved.  Length,  one  inch 
and  three-fourths,  breadth  of  the  buckler  one  inch 
and  one-fourth. 

This  species  resembles  a  little  the  C.  Pulchella  of 
Dalman.  The  specimen  from  which  the  model  was 
taken,  is  in  the  possession  of  Mr.  R.  Peale,  of  New 
York,  who  willingly  lent  it  for  this  monograph.  He 
informed  me  that  it  was  found  in  the  state  of  New 
York,  but  he  was  unable  to  name  its  precise  locality. 
It  occurs  in  a  soft  ash  coloured  limestone.  No  other 
petrifaction  is  observable  in  the  fragment  of  rock 
which  contains  it. 

CALYMENE  PLATYS.*     Green.     Casts  No.  4  and  5. 

Clypeo  antice  rotundatoj  prominentia  frontal! 
utrinque  quatuor  tuberculis. 

The  buckler  is  probably  semilunatej  but  as  the  an- 
terior portion  is  lost,  this  cannot  be  determined  with 
precision.  The  posterior  raised  rim  is  not  continu- 
ous, as  in  the  C.  Selenecephala>  but  is  separated  by 
the  longitudinal  dorsal  furrows.  The  front  is  distinct* 
ly  divided  from  the  cheeks,  and  has  four  tubercular 
prominences  on  each  side.  Three  of  them  are  near- 
ly on  a  line  with  the  lateral  edge  of  the  cheeks,  and 
gradually  diminish  in  size,  as  they  descend  to  the 
anterior  part  of  the  buckler.  The  other  is  smaller, 
and  is  between,  and  a  little  to  the  side,  of  the  upper 

*  From  a  Greek  work  which  signifies  Flat, 


33 

two.  The  cheeks  form  spherical  triangles.  The  ocu- 
liferous  prominences  are  close  to  the  second  large 
tubercle  on  the  front.  The  cheeks  are,  however, 
quite  imperfect.  The  articulations  of  the  back  can- 
not be  distinguished  from  those  of  the  tail.  In  our 
specimen  they  are  all  beautifully  distinct,  and  are 
twenty-two  in  number.  The  posterior  raised  rim  of 
the  buckler  seems  to  form  an  articulation;  its  ex- 
tremities on  each  side  are  a  good  deal  thickened  and 
expanded.  The  costal  arches  suddenly  curve  down- 
wards and  backwards,  near  their  middle,  so  as  to  di- 
vide the  abdomen  and  tail  into  five  unequal  sections. 
The  whole  length  is  nearly  three  inches.  The 
breadth  of  the  buckler  nearly  two  inches. 

This  fine  large  Calymene  was  accidentally  disco- 
vered on  the  Helderberg  mountain,  by  my  friend, 
Professor  T.  R.  Beck.  One  of  the  loose  pieces  of 
sandstone  rolling  over,  near  his  feet,  presented  him 
the  fine  natural  mould,  from  which  he  has  kindly  per- 
mitted our  cast  to  be  taken.  The  animal  relic  once 
enclosed  in  this  matrix,  must  still  be  near  that  locali- 
ty, and  yet  remains  undiscovered,  to  reward  the  en- 
terprise of  some  more  fortunate  naturalist. 

One  of  our  models  represents  the  natural  mould 
found  by  Dr.  Beck.  The  other  is  a  cast  taken  from 
it  and  exhibits,  more  satisfactorily,  the  various  parts 
of  the  animal. 


34 

CALYMENE  MICROPS.*     Green.     Cast  No.  6. 

Clypeo  antice  subattenuato;' occulis  minimis  in 
lateribus  capitisj  abdominis  articulis  a  14  ad  18$  cor- 
pore  depresso. 

The  buckler  is  semielliptical,  slightly  punctate,  and 
much  depressed  anteriorly  \  the  front  and  cheeks  are 
not  very  distinctly  marked.  The  eyes  are  very  re- 
mote from  each  other,  being  situated  near  the  poste- 
rior lateral  angles  of  the  head.  They  are  not  very 
prominent,  and  exhibit  no  marks  of  being  reticulated. 
Before  the  eye  on  each  side,  there  is  a  slight  trans- 
verse indentation.  It  is  difficult  to  distinguish  the 
articulations  of  the  abdomen  from  those  of  the  tail. 
They  are  from  fourteen  to  eighteen  in  number.  Where 
the  lateral  lobes  remain  perfect,  two  narrow  raised 
lines  appear  between  each  of  the  ribs;  these  are  most 
evident  on  the  caudal  extremities  of  the  animal.  The 
middle  lobe  is  in  the  form  of  a  long,  slender,  and 
acute  cone.  The  whole  animal  is  an  inch  and  a  quar- 
ter long,  and  is  much  more  depressed  than  any  other 
Calymene  which  we  have  seen. 

I  am  indebted  to  Mr.  Titian  R.  Peale  for  the  use  of 
the  original  from  which  our  model  was  taken,  his  li- 
berality to  those  who  cultivate  Natural  History  is 
proverbial,  and  needs  no  encomium  from  me.  The 
C.  Microps  is  said  to  have  been  found  near  Ripley, 
Ohio.  It  occurs  in  black  limestone. 

The  eyes  of  this  Calymene  are  small  in  compari- 

*  From  the  Greek  for  "  small  eyes." 


35 

son  with  those  of  some  other  species — particularly 
the  C.  Bufo,  C.  Macrophthaima,  and  C.  Anthiops. 

CALYMENE  ANCHIOPS.*     Green.    Cast  No.  7. 

Clypeo  antice,  caudaque  postice  rotundatis;  oculis 
approximis,  magnis,  excertisj  articulis  vigenti$  cor- 
pore  piano. 

The  buckler  of  this  species  is  irregularly  hemis- 
pherical $  the  front  pyriform  and  without  pustula- 
tions.  The  cheeks  are  almost  entirely  occupied  by 
the  eyes,  which  are  placed  very  near  each  other  on 
the  upper  part  of  the  forehead ;  are  very  large  and 
trilobate,  the  side  lobes  being  elongated  and  at- 
tenuated in  front.  The  articulations  of  the  back  are 
twenty  in  number,  those  of  the  abdomen  not  being 
distinguishable  from  those  of  the  tail.  The  costal 
arches  of  the  side  lobes  are  round  near  their  extremi- 
ties, and  are  intersected  with  two  or  three  raised 
lines.  Length  nearly  four  inches.  Breadth  about 
two  inches. 

It  gives  me  great  satisfaction  in  being  able  to  de- 
scribe, and  to  present  to  naturalists  a  good  cast  of 
this  Calymene,  which  has  excited  for  a  long  time  so 
much  interest  and  perplexity.  The  original  fossil 
from  which  our  plaster  model  was  made  is  now  de- 
posited in  the  cabinet  of  the  Albany  Institute,  and  is 
the  identical  specimen  from  which  a  cast  was  long 
since  made,  by  Dr.  Hosack  of  New  York,  a  specimen 

*  From  two  Greek  words  which  signify  "  eyes  approximate." 


36 

of  which  he  sent  in  July,  1819,  to  the  Royal  Acade- 
my of  Science,  in  France.  Professor  Brongniart  re- 
ferred the  animal  from  which  this  model  was  taken, 
though  with  much  hesitation  and  doubt,  to  the  spe- 
cies, Calymene  Macrophthalma.  He  remarks  con- 
cerning it,  "  II  est  beaucoup  plus  gros  que  les  autres 
indiviclus,  et  a  pres  de  neuf  centimetres  de  longueur. 
C'est  avec  doute  que  je  rapporte  cette  empreinte 
tres-peu  nette  a  Pespece  actuelle;  mais  malgre  ses 
formes  obtuses,  et  1'absence  de  tout  detail,  elle  est  si 
remarquable  par  la  grosseur  de  ces  yeux  et  par  le 
prolongement  de  son  bouclier  qu'on  peut  presumer 
qu'elle  appartient  an  calymene  macrophthalme,  et 
avec  d'autant  plus  de  probabilite  qu'elle  vient  aussi 
des  Etats  Unis  d'Amerique.  Elle  a  etc  trouvee, 
suivant  M.  Hosack,  dans  un  schiste."  We  have  seen 
the  cast  alluded  to  in  the  above  note,  and  are  not  at 
all  surprised  at  the  uncertainty  which  it  has  occa- 
sioned. The  apparent  prolongation  of  the  buckler  is 
entirely  occasioned  by  the  loss  of  a  small  fragment 
from  that  portion  of  the  head.  The  form  and  posi- 
tion of  the  eyes,  further  distinguish  it  from  any  of 
the  numerous  specimens  of  C.  Macrophthalma,  that 
we  have  examined.  The  raised  lines  which  we  have 
noticed  as  intersecting  the  costal  arches  of  the  lateral 
lobes  are  remarkable,  though  they  may  have  been 
produced  by  accidental  fissures  in  the  epidermal 
covering  of  the  animal.  The  head  of  the  C.  Ma- 
crophthalma is  always  marked  by  minute  and  promi- 
nent granulations,  like  shagreen — nothing  of  this  kind 
appears  on  the  buckler  of  the  C.  Anchiops. 


37 

I  am  informed  by  my  friend,  Dr.  T.  R.  Beck,  to 
whose  liberality  I  owe  this  interesting  species,  that  it 
was  found  in  Ulster  county,  New  York.  It  was  sup- 
posed by  Dr.  Hosack)  to  have  been  discovered  in  the 
vicinity  of  Albany.  Respecting  the  locality  and  geo- 
logical relations  of  this  trilobite,  Professor  Brong- 
niart  remarks,  "  un  modele  en  platre  de  trilobite  en- 
voye  a  I'Acaclemie  des  Sciences,  en  Juillet,  1819, 
par  M.  Hosack,  et  que  j'ai  rapporte,  autant  que  la 
chose  etait  possible,  et  toujours  avec  doute,  au 
calymene  macrophthalme,  a  etc  trouve  dans  le  terri- 
toire  d'Albany,  etat  de  New  York.  Or,  les  environs 
de  cette  ville  sont  indiques,  sur  la  carte  geologique  de 
M.  Maclure,  comme  formes  de  terrains  de  transition. 
M.  Hosack  dit  qu'il  a  etc  trouve  au  milieu  d'un 
rocher  ardoise,  c'est  a  dire,  dans  un  schiste  proba- 
blement  analogue  a  celui  des  environs  d'Angers,  qui 
renferme  les  Ogygies,  et  ce  trilobite  ce  rapproche  un 
peu  de  ce  genre  par  la  grosseur  des  tubercules  qui 
recouvrent  les  yeux  on  en  tiennent  la  place."  The 
rock  in  which  the  Calymene  Anchiops  is  found,  ap- 
pears to  be  a  clay  slate. 

CALYMENE  DIOPS.*     Green.     Cast  No.  8,  and  fig.  2. 

Clypeo  lobato  piano;  rugis  tribus  in  lateribus 
frontis;  tuberculis  oculiformibus,  eminentissimis  et 
duplicibus;  articulis  octodecim;  cauda  rotunda. 

This  species  is  very  distinct  from  every  other  Caly- 
mene that  we  have  seen.  The  outline  of  the  buckler  is 

*  From  the  Greek  for  "  Double  Eyes." 

D 


38 

lobate  lunate;  the  front  is  very  convex,  and  a  good 
deal  elevated  above  the  cheeks  or  sides,  from  which 
it  is  divided  by  a  deep  furrow;  on  the  posterior  mar- 
gin of  the  front  on  each  side,  close  to  the  groove  there 
is  a  prominent  circular  tubercle,  before  which  there 
are  three  small  transverse  wrinkles.  The  cheeks  are 
subtriangular;  the  oculiform  tubercle  is  near  the  pos- 
terior superior  angle,  and  is  only  separated  from  the 
tubercle  on  the  front,  by  the  furrow  or  groove,  so  that 
the  animal  seems  to  have  had  double  eyes  on  each 
side;  there  are  two  curved  lines  on  each  side  below 
the  eyes,  crossed  near  the  front  by  a  deep  short  canal. 
The  middle  lobe  of  the  abdomen  and  tail  is  rather 
longer  than  the  lateral  lobes,  and  is  rounded  and  very 
prominent  throughout.  It  is  composed  of  18  articu- 
lations, seven  of  which  appear  to  belong  to  the  tail; 
it  is,  however,  somewhat  difficult  to  define  the  length 
of  the  tail  with  precision.  The  costal  arches  of  the 
lateral  lobes,  particularly  those  near  the  tail,  are 
bifurcate.  Length  almost  three  inches. 

The  original  fossil,  from  which  the  cast  was  taken, 
is  in  the  New  York  Museum.  I  am  indebted  to  Mr. 
Rubens  Peale,  the  liberal  proprietor  of  that  flourish- 
ing and  important  institution,  not  only  for  the  use  of 
it  in  this  Monograph,  but  also  for  some  valuable  in- 
formation relating  to  other  species.  The  precise 
locality  of  Mr.  Peale's  specimen  is  not  known,  but 
in  the  cabinet  of  J.  P.  Wetherill,  Esq.,  there  is  a  fine 
head  of  the  C.  diops  which  was  found  in  the  State  of 
Ohio.  Both  specimens  are  mineralized  by  the  same 
kind  of  soft  grey  coloured  limestone — and  I  have 


39 

but  little  doubt  that  they  were  derived  from  the  same 
place. 

CALYMENE  MACROPHTHALMA.*  Brongniart.  Cast  No.  9. 

Clypeo  antice,  caudaque  postice  attenuatis,  oculis 
magnis  exsertis. 

This  species,  according  to  Al.  Brongniart,  who  first 
described  it,  is  remarkable  for  the  magnitude  and 
protuberance  of  its  eye-shaped  tubercles,  and  by  the 
prolongation  of  the  anterior  portion  of  the  buckler, 
in  the  form  of  a  snout. 

The  back  is  marked  by  .12  or  13  articulations, 
which  are  thicker  than  those  of  the  tail.  The  tail  is 
short,  pointed,  and  without  expansion. 

The  middle  lobe,  or  front  of  the  buckler,  in  this 
calymene,  is  said  by  Brongniart  to  be  marked  on 
its  sides  by  three  oblique  plicae  or  wrinkles,  but  we 
have  not  been  able  to  discover  this  character  in  any 
of  the  specimens  to  which  we  have  access;  neither 
do  they  exhibit  any  remarkable  prolongation  in  the 
anterior  portion  of  the  buckler,  as  stated  in  his  spe- 
cific character.  The  specimens  which  we  have  exa- 
mined, agree  pretty  well  with  the  representation  he 
has  given  of  the  C.  Macrophthalma,  Plate  I.  fig.  5.  A. 
B.  Sc  C.  made  from  a  drawing  by  Mr.  Stokes,  from 
a  fossil  found  in  Coalbrookdale,  (Eng.) 

This  trilobite  is  common  in  several  parts  of  the 

*  From  the  Greek  for  "  Great  eyes." 


40 

United  States.  According  to  Dr.  J.  E.  Dckay,*  the  C. 
Macrophthalma  is  found  on  the  Helderbergmountains, 
near  Albany,  and  at  Coshung  creek,  not  far  from 
Seneca  lake,  in  the  State  of  New  York.  It  occurs 
also  at  Leheighton,  in  Pennsylvania — at  the  Falls  of 
the  Ohio,  and  at  several  other  localities.  We  have 
examined  a  number  of  specimens  of  the  C.  Macroph- 
thalma, contained  in  the  rich  cabinet  of  fossils,  in 
the  Academy  of  Natural  Sciences,  and  have  never 
seen  any  individual  which  resembles  the  fig.  4,  Plate 
I.  of  Brongniart;  and  in  no  instance  is  the  front  of 
the  buckler  marked  by  three  oblique  folds,  a  charac- 
ter stated  as  peculiar  to  this  species.  The  C.  Macroph- 
thalma, (variety)  occurs  in  large  quantities  in  Le- 
heighton in  Pennsylvania,  and  we  arc  indebted  to 
Mr.  D.  Keim,  for  some  fine  specimens  from  that  lo- 
cality. 

The  authority  of  Professor  Brongniart  is  sufficient 
to  place  the  C.  Macrophthalma  among  the  species  of 
the  United  States,  though  we  have  been  unable  fully 
to  identify  it  with  his  description.!  He  received  a 

*  See  Annals  of  Lyceum,  Vol.  I.  p.  188. 

t  We  have  seen  in  the  Cabinet  of  Mr.  Featherstonhaugh,  a  fine 
group  of  trilobites,  in  the  transition  limestone,  from  Dudley, 
(Eng.)  Among  them  there  is  a  perfect  head,  which  agrees  ex- 
actly with  the  description  given  by  Mr.  Brongniart  of  the  head 
of  his  Calymene  Macrophthalma.  If  this  belongs  to  the  true 
macrophthalma,  our  species  under  that  name  is  entirely  distinct. 
Since  our  work  had  been  prepared  for  the  press,  Dr.  J.  J.  Cohen, 
of  the  Baltimore  College,  has  shown  us  the  fragment  of  a  caly- 
mene  from  Berkley,  Virginia,  which  agrees  with  Bvongniart's  de- 


41 

specimen,  transformed  into  red  jasper,  from  Prof. 
Ducatel,  said  to  be  found  in  the  United  States — no 
precise  locality  is  given.  Our  model  represents  the 
animal  which  is  supposed  to  be  the  one  intended  by 
Brongniart  as  the  C.  Macrophthalma  of  North  Ame- 
rica. It  is,  in  our  opinion,  a  variety  gf  the  C.  Bufo. 
There  can  be  no  doubt  that  several  species  have  been 
confounded  under  the  name  of  C.  Macrophthalma. 

The  following  extract  of  a  letter  from  Professor 
Ducatel  to  the  author,  referring  to  the  locality  of  this 
species,  will  be  read  with  interest. 

"  I  cannot  be  positive  as  to  my  recollection  of  the 
locality  of  the  fossil  referred  to  by  Brongniart  and 
yourself,  but  believe  it  is  one  of  several  found  by  my 
friend  Dr.  M'Culloh,  in  the  neighbourhood  of  Berk- 
ley Springs,  Virginia.  I  regret  that  I  have  not  in 
my  possession  another  specimen  to  present  to  you." 

CALYMENE  BUFO.     Green.     Cast  No.  10. 

Clypeo  rotundato,  convexo,  punctato;  abdominis 
articulis  sexdecimj  cauda  attenuata;  corpore  piano. 

Buckler  semilunate,  front  very  large,  rounded  be- 
fore and  arcuated  at  the  insertion  of  the  middle  lobe; 
surface  convex,  and  marked  with  numerous  depressed 
pimples.  Mouth  large,  lunate,  resembling  that  of  a 

scription  of  the  macrophthalma,  and  with  the  above  fossil  from 
Dudley.  We  regret  that  the  imperfection  of  the  fossil  prevents 
our  giving  a  satisfactory  cast  of  it. 

D  2 


42 

toad  or  frog,  with  a  narrow  raised  rim  on  the  upper 
and  under  lip.  Below  the  chin  there  are  no  pustula- 
tions.  Cheeks  small,  triangular,  and  separated  from 
the  front  by  a  deep,  rectilinear  furrow;  the  eyes  in 
our  specimen  are  much  injured,  but  they  are  large, 
and  near  the  upper  angle  of  the  cheeks.  Middle  lobe 
with  a  series  of  distinct  double  articulations.  Lateral 
lobes  wider  than  the  middle  lobe,  ribs  deeply  grooved 
near  their  insertion;  articulations  of  the  abdomen 
twelve;  of  the  tail  ten.  Length  four  inches  and  a 
half;  breadth  of  the  buckler  nearly  two  inches. 

This  fossil  was  presented  to  me  some  time  since 
by  Thomas  P.  Johnson,  Esq.,  who  mentioned  that  it 
was  found  in  New  Jersey,  but  that  he  could  not  learn 
its  precise  locality.  Near  Patterson,  in  that  State, 
some  trilobites  have  been  discovered — perhaps  the 
C.  Bufo  may  have  been  derived  from  that  locality.  It 
is  composed  of  a  dark  greyish  limestone,  easily  cut 
with  a  knife. 

CALYMENE  BUFO.    Variety,  RANA.    Cast  Nos.  1 1  &  12. 

This  fine  specimen  differs  from  the  one  above  de- 
scribed, in  having  the  front  of  the  buckler  rather 
smaller,  and  of  a  different  contour.  The  whole  of 
the  shell  is  also  covered  with  granulations,  which 
only  appear  on  the  head  of  the  other;  this,  however, 
may  be  only  an  imperfection  in  the  specimens  in  our 
cabinet. 

I  am  indebted  to  the  Albany  Institute  for  the  origi- 
nals of  the  models  Nos.  11  &  12.  They  were  found  at 


43 

Seneca,  Ontario  County,  New  York,  in  dark,  slaty 
limestone,  which  also  contains  cubical  crystals  of 
iron  pyrites.  A  fortunate  blow  of  the  hammer  has 
fractured  the  rock  which  contains  this  trilobite,  so 
neatly,  as  to  present  us  at  the  same  time  with  the 
petrified  animal  in  an  almost  perfect  state,  and  also 
with  the  mould  or  matrix  in  which  it  was  imbedded. 
This  arrangement  is  beautifully  illustrated  by  our 

models. 

% 

GENUS  ASAPHUS.     Brongniart. 

This  genus  derives  its  name  from  the  Greek  word 
Arctpvs — obscure.  It  embraces  perhaps  more  species 
than  any  other  genus  of  the  family  of  trilobites. 
About  twenty  have  already  been  discovered.  Most 
of  them  are  very  characteristic  and  can  easily  be  de- 
termined, but  as  the  genus  Asaphus,  is  intermediate 
between  Calymene  and  Ogygia,  it  is  sometimes  a 
little  difficult  to  decide  the  genus  to  which  the  inos- 
culating species  on  each  side,  belongs. 

In  general,  the  Asaphs  may  be  known  by  the  body 
being  very  much  depressed,  and  by  the  membranaceous 
development,  which  extends  beyond  the  lateral  lobes. 
The  middle  lobe  of  the  abdomen,  is  rarely  more 
than  one-fifth  the  width  of  the  body.  As  the  abdo- 
men and  tail  of  the  Asaph  are  the  only  portions  of 
the  animal  commonly  found  entire,  the  distinctive 
characters  of  the  genus  above  given,  may  generally 
be  ascertained. 

Professor  Brongniart  remarks,  that  the  ribs  of  the 
which  correspond  in  number  and  position  to 


44 

the  articulations  of  the  middle  lobe,  "  are  sometimes 
simple  or  undivided,  at  least  in  the  post  abdomen, 
but  that  they  are  always  bifurcated  in  the  Calymene" 
As  far  as  our  observations  have  extended,  these  re- 
marks do  not  apply  either  in  the  one  case  or  the 
other. 

The  head  or  buckler  of  the  rfsaph,  is  not  so  deeply 
divided  into  three  lobes  as  the  Calymene;  they  are, 
however,  quite  distinct.  The  oculiferous  tubercles 
are  in  some  species  exceedingly  well  marked  by  a  re- 
ticulated structure. 

This  genus  often  occurs  at  the  same  localities  with 
the  Calymene,  though  in  some  instances  it  seems  to 
occupy  rocks  peculiar  to  itself.  Dr.  John  Bigsby,  in 
his  list  of  organic  remains  occurring  in  the  Caiiadas, 
states,  that  he  never  found  a  single  species  of  the 
genus  Calymene,  on  the  north  side  of  the  River  St. 
Lawrence,  although  the  Asaphs  were  very  abundant.* 
In  his  Sketch  of  the  Geology  of  the  Island  of  Mon- 
treal, he  however  observes:  "  Of  Trilobites,  the 
Asaph  genus  is  the  most  abundant,  they  approach 
nearest  the  species  caudatus,  of  Brongniart.  I  have 
found  no  entire  Calymene,  but  many  bucklers  or  heads 
of  the  Blumenbach  species,  some  of  them  an  inch 
and  a  half  in  diameter.  They  are  found  whole  in 
considerable  numbers  in  the  vicinity  of  Quebec. "f 

*  Silliman's  Journal,  vol.  viii.  p.  83. 

t  Annals  New  York  Lyceum,  vol.  i.  p.  214. 


45 


ASAFHUS  L ATI co STATUS.*     Green.     Cast  No.  13. 

Cauda  praelonga,  pars  ad  marginem  vix  membra- 
nacea;  cute  coriacea,  tuberculis  minimis;  costis  lads, 
convexis  et  valde  clistinctis. 

The  fragments  of  this  species,  which  we  have  exa- 
mined, comprise  ten  articulations  of  the  middle  lobe, 
and  the  corresponding  ribs  of  the  sides,  all  in  a  very 
good  state  of  preservation;  the  extent  to  which  the 
membranaceous  expansion  reached  beyond  the  tail  and 
the  lateral  lobes  is  very  apparent,  but  it  has  been  un- 
fortunately broken  off  all  round.  Our  specimen  ap- 
pears to  be  a  natural  cast  of  the  internal  part  of  the 
shell,  or  the  coriaceous  covering  of  the  animal. 

The  portion  of  this  specimen  of  trilobite  which 
still  remains  perfect,  is  two  inches  long,  and  three 
inches  and  a  quarter  broad.  The  middle  lobe  exhi- 
bits the  appearance  of  a  very  exact  and  gradually  ta- 
pering cone,  its  articulations  being  rounded  and 
slightly  flattened  on  the  top.  The  ribs  of  the  lateral 
lobes  are  nearly  straight,  slightly  arched,  broad, 
rounded,  and  gradually  increase  in  width  from  the 
point  of  their  insertion;  they  are  simple  or  not  bifur- 
cated throughout,  and  are  covered  with  very  minute 
granulations,  which  are  probably  produced  by  the 
sandstone  in  which  the  animal  is  mineralized.  The 
membranaceous  expansion  near  the  caudal  termina- 
tion, is  a  good  deal  prolonged. 

The  A.  Laticostatus  occurs  in  a  light  coloured  fer- 

*  From  the  Latin  for  "  broad  ribbed." 


46 

rugenious  sandstone,  which  contains  a  multitude  of 
other  fossil  remains,  particularly  a  large  species  of 
Productus  and  of  Terebratula.     It  is  said  to  have 
been  found  in  Ulster  county,  in  the  State  of  New 
York,  by  the  late  Charles  Wilson  Peale,  Esq.,  the 
distinguished  founder  of  the  Philadelphia  Museum. 
During  the  memorable  search  after  the  bones  of  the 
Mastodon  Giganteum,  in  the  marl  pits  of  that  county, 
this  enterprising  naturalist  procured  our  Asaph  with 
many  other   remarkable   petrifactions.     The    rocks 
which  contain  them  were  probably  found  not  in  situ^ 
but  were  masses  rolled  from  the  neighbouring  Shaw- 
angunk  mountains,*  which  by  some  geologists  are 
supposed  to  be  a  link  in  the  grand  chain  of  the  Alle- 
ghanies.  Mr.  R.  Peale,  of  New  York,  lately  visited  the 
rich  repository  of  fossils  in  Ulster  County,  and  pro- 
cured a  number  of  specimens  of  the  A.  Laticostatus, 
all  of  which  he  has  kindly  permitted  me  to  examine. 
These  are  much  smaller  than  our  cast,  but  in  many 
instances    the    caudal   elongation    is    perfectly   de- 
veloped.    The   A.  Laticostatus   also    occurs   in  the 
Helderberg  mountains,  specimens  of  which  are  in  the 
Albany  Institute. 

ASAPHUS  SELENURUS.!     Eaton.     Casts  Nos.  14  &  15. 

Cauda  semilunarij  costis  angustis,  valde  distinctis; 
abdominis  articulis  duodecim;  corpore  convexo. 

*  The  Lenape  tribe  of  Indians,  who  formerly  inhabited  this 
district  of  country,  gave  the  name  of  Shawangunk  to  this  stu- 
pendous ridge  of  hills — a  name  which  has  been  very  properly  pre- 
served. 

t  Derived  from  Selene,  moon,  and  ouros,  tail. 


47 

I  am  indebted  to  Professor  Eaton,  for  two  speci- 
mens of  this  very  interesting  species.  In  his  Geolo- 
gical Text  Book,  he  thus  describes  it:  "  Tail  cres- 
cent-form, or  concavo-convex,  with  the  convex  side 
forward,  upon  which  the  post  abdomen  terminates: 
abdomen  contains  about  1 2  articulatious,  with  an  ab- 
rupt termination  equal  in  breadth  to  one-fourth  of 
the  length  of  the  transverse  lunate  tail;  the  articula- 
tions of  the  side  lobes  gradually  incline  towards  the 
axis  of  the  body,  until  the  last  pair  terminate  at  the 
tail.  Found  in  transition  limestone  at  Glenn's  Falls, 
and  Becroft's  mountain,  near  Hudson.  I  have  a  spe- 
cimen from  Becroft's  mountain,  with  part  of  the 
original  covering  of  the  animal  remaining." 

When  we  first  noticed  the  remarkable  lunate  ap- 
pearance of  the  tail  of  this  Asaph,  we  supposed  that 
it  was  occasioned  by  some  accident,  but  there  seems 
no  doubt  that  this  conformation  is  natural.  In  our 
specimens  of  this  species,  which  are  not  however  per- 
fect, the  articulations  of  the  abdomen  do  not  exceed 
8  in  number.  The  representation  of  this  animal  re- 
main given  by  Mr.  Eaton,  plate  1,  figure  1,  is  exceed- 
ingly inaccurate;  it  will  confuse  rather  than  illustrate 
the  subject.  Our  cast  and  the  drawing,  we  believe, 
are  taken  from  the  same  specimen,  which  was  kindly 
loaned  by  Mr.  Eaton  for  this  work.  It  is  but  jus- 
tice to  the  amiable,  industrious,  and  indefatigable  au- 
thor of  the  Geological  Text  Book  to  remark,  that  he 
regrets  as  much  as  any  one,  the  insufficiency  of  his 
figures  of  the  trilobites,  to  give  any  correct  idea  of 
the  fossils  they  are  intended  to  represent. 


48 

In  the  cabinet  of  the  Albany  Institute  there  are  a 
number  of  specimens  of  the  A.  Selenurus.  One  of 
our  models  represents  the  natural  mould  made  by 
the  animal  in  the  rock;  the  other  is  an  impression 
taken  from  it,  in  order  to  exhibit  the  animal  in  a 
more  satisfactory  manner. 

ASAPHUS  LIMULURUS.*     Green.     Cast  No.  16. 

Cauda  longa,  spina  munita  sicut  in  Limulo;  costis 
abdominis  in  spinis  retrorsum  flexis,  desinentibus. 

It  is  very  much  to  be  regretted  that  the  abdomen 
and  caudal  end  only  of  this  remarkable  Asaph  have 
hitherto  been  discovered;  it  is,  however,  exceedingly 
gratifying  that  the  fragment  still  remains  in  so  per- 
fect a  state.  It  forms  a  part  of  the  magnificent  cabi- 
net of  organic  remains  belonging  to  J.  P.  Wetherill, 
Esq.,  now  deposited  in  the  Academy  of  Natural 
Sciences,  of  Philadelphia. 

Dr.  J.  J.  Cohen  discovered  a  small  specimen  of 
this  species  at  Lockport,  New  York,  which  he  has 
presented  to  the  Athenaeum,  in  Baltimore. 

Eight  articulations  of  the  abdomen,  and  ten  of  the 
tail,  are  all  of  this  fine  species  that  we  have  seen. 
The  ribs,  or  costal  arches  of  the  abdomen  have  a 
deep  furrow  on  their  upper  surface,  commencing  at 
the  middle  lobe,  and  terminating  near  their  free  ex- 
tremities; these  extremities  appear  all  detatched  from 
each  other,  and  end  in  reflected  points  or  spines,  so  as 

*  From  two  Greek  words,  which  signify  "  Limulus  tailed." 


49 

to  give  the  side  of  ^the  animal  a  serrate  appearance. 
The  costal  arches  of  the  tail  are  grooved  through 
their  whole  extent,  and  present  no  spinous  termina- 
tions. Beyond  the  membranaceous  expansion  of  the 
tail,  which  is  somewhat  similar  to  that  of  the  Asa- 
phus  Caudatus,  there  projects  a  single  spine,  like 
that  from  the  tail  of  the  Limulus  polyphemus;  this 
spine  may  be  traced  under  the  caudal  membrane  to  its 
insertion  into  the  middle  lobe.  A  portion  of  the 
crustaceous  shell  is  still  entire,  and  it  seems  to  have 
been  covered  with  very  minute  granulations.  A 
row  of  large  granulations  may  easily  be  traced  on 
each  side  of  the  middle  lobe.  Length  of  the  frag- 
ment, one  inch  and  a  half.  Breadth  one  inch  and  a 
fourth. 

The  A.  Limulurus  was  found  in  the  dark  brown, 
shaly  limestone,  at  Lockport,  in  the  State  of  New 
York;  it  is  associated  in  the  same  rock  with  the 
terebratula.  and  several  other  fossils. 

The  singular  spinous  projection  from  the  tail  of 
this  Asaph,  furnishes  another  analogy,  between  the 
trilobite  and  the  limulus;  an  affinity  which  was  sug- 
gested by  Dr.  Dekayj  and  which  has  been  argued 
with  great  ingenuity  both  by  himself  and  Professor 
Wahlenberg.* 

'*  See  Nova  Acta  Regise  Societatis  Upsalensis:  1821.  Also, 
Annals  of  the  Lyceum  of  Natural  History.  New  York.  Vol.  i. 
pages  179—185, 


50 


ASAPHUS   CAUDATXJS.*      Briinnich.     Brongn,     Cast 
No,  17. 

Clypeo  antice  subrotundato,  postice  valde  emargi- 
nato,  angulo  externo  in  mucronem  productoj  oculis 
exsertis,  conicis,  truncatis,  distincte  reliculatisj  post 
abdomine  in  caudam  membranaceam,acutam  extenso. 
(Vide  Brongniart.) 

The  middle  lobe  of  the  buckler  is  marked  by  three 
transverse  plicae  or  folds  on  its  posterior  part,  and 
its  cheeks  or  lateral  portions  are  triangular^  the  pos- 
terior exterior  angles  of  which,  are  acute,  and  con- 
siderably elongated.  The  cheeks  are  furnished  with 
conical,  truncated,  semilunar  and  externally  convex 
tubercles,  which  were  beyond  all  doubt  the  eyes  of  the 
animal,  being  reticulated  as  in  those  of  the  Limulus. 
The  middle  lobe  of  the  back  is  narrow,  and  has  twelve 
articulations.  The  lateral  lobes  are  composed  of 
double  ribbed  costal  arches.  Beyond  the  lateral  lobes 
and  the  caudal  termination,  there  is  a  smooth,  thick 
membranaceous  expansion,  which  forms  an  acute 
projection  below  the  central  portion  of  the  tail. 

The  specimen  in  the  Philadelphia  Museum,  by 
which  I  have  identified  this  species,  is  marked  as 
coming  from  Ripley,  Ohio.  It  reposes  on  a  frag- 
ment of  ash  coloured  limestone — which  contains  also 
a  mutilated  specimen  of  what  seems  to  be  a  calymene, 
and  a  few  small  terebratulse,  Sec. 

*  From  the  Latin  word  for  "  tailed," 


51 

Dr.  John  Bigsby,  in  his  "  List  of  Organic  Re- 
mains, occurring  in  the  Canadas,"  states  that  the 
A.  caudatus  is  frequently  met  with,  thrown  up  by  the 
water  on  the  north  shore  of  Lake  Superior — on  the 
bank  of  Rainy  river—at  the  Lake  of  the  Woods,  and 
at  several  other  places.  In  some  localities  they  are 
astonishingly  numerous,  and  so  small  as  to  be  almost 
microscopic.  They  occupy  indiscriminately  lime- 
stone of  every  colour,  but  are  most  numerous  in  that 
which  is  brown  or  crystallized.  They  are  composed 
of  the  kind  of  limestone  in  which  they  happen  to  be 
embedded. 

We  have  seen  a  number  of  specimens  of  this  species 
in  the  Albany  Institute,  in  Mr.  Wetherill's  cabinet, 
and  in  the  Baltimore  Athenseum;  but  in  all  of  them, 
the  abdomen  and  caudal  extremity  only  remain  per- 
fect: from  their  exact  resemblance,  however,  to  the 
same  parts  of  the  A.  caudatus,  figured  by  Brongniart, 
(plate  2,  fig.  4,  D.)  we  have  no  hesitation  with  regard 
to  their  identity.  The  description  which  we  have 
given  of  the  buckler^  supposed  to  belong  to  our  Asaph, 
is  therefore  taken  from  Brongniart,  whose  specimens 
were  found  at  Dudley,  the  celebrated  locality  of  the 
C.  Blumenbachii.*  The  coriaceous  membrane,  which 
extends  beyond  the  lateral  lobes  and  forms  the  caudal 

*  In  the  first  volume,  2d  series,  of  the  Transactions  of  the 
Geological  Society  of  London,  Mr.  Weaver  has  published  some 
highly  interesting  observations  on  the  fossils  found  in  Glouces- 
tershire, England.  The  A.  caudatus,  he  states,  is  there  found 
in  the  transition  limestone,  though  very  much  mutilated.  (Vide 
p.  326.) 


52 

termination  of  our  species,  is  not  covered  with  ini- 
nute  dots,  as  in  the  European  fossil;  and  if  a  new 
name  is  to  be  applied  to  it  on  that  account,  it  may  be 
called  A.  glabratus*  M.  Wahlenberg,  has  given 
the  figure  of  a  trilobite  which  he  calls  caudatus,  but 
ours  cannot  be  mistaken  for  that  species,  to  which 
Brongniart  has  very  judiciously  applied  the  name  of 
A.  meucronatus. 

The  conical  eye-like  protuberances  on  the  head  of 
this  species,  are  very  remarkable,  and  so  much  re- 
semble the  reticulated  eyes  of  the  limulus,  as  to 
leave  no  doubt  that  they  once  contained  the  organs 
of  vision. 

ASAPHUS  HAUSMANNI.     Brongniart. 

Cauda  rotundata;  cute  coriacea  tuberculis  mini- 
mis  spinulosis  tectu. 

In  De  la  Beche's  Geological  Manual,  there  is  a 
list,  of  the  trilobites  which  have  been  discovered  in 
the  grawacke  group  of  rocks.  This  list  we  have 
given  in  our  introduction.  Among  the  trilobites  he 
states  that  the  Asaphus  Hausmanni  has  been  found 
in  the  United  States;  as  we  have  not  seen  the  species, 
and  presuming  the  author  to  be  correct  in  his  locali- 
ty, we  give  the  following  description  from  Professor 
Brongniart. 

*  In  the  cabinet  of  G.  W.  Featherstonhaugh,  Esq.,  I  have  ex- 
amined a  fine  specimen  of  the  A.  caudatus,  from  Dudley,  Eng- 
land, but  could  not  perceive  the  minute  dots  on  the  tail,  as  men- 
tiojned  by  Brongniart. 


53 

I  know,  he  observes,  only  the  tail  of  this  Asaph, 
but  it  is  so  different  from  that  of  other  trilobites,  that 
I  do  not  hesitate  to  establish  a  particular  species, 
upon  the  consideration  of  this  part  alone.  Its  gene- 
ral form  is  that  of  a  semi-ellipsis;  the  middle  lobe  re- 
presents a  very  slender  cone.  The  arched  ribs  of  the 
lateral  lobes  are  perfectly  distinct  and  simple.  I  can- 
not perceive  in  them  the  slightest  appearance  of  bi- 
furcation. This  sufficiently  characterizes  the  species. 
But  that  which  further  distinguishes  it  from  the 
others,  are  the  small,  elevated  points,  scattered,  and 
of  course  rough  (serres),  with  which  the  skin  or  epi- 
dermis is  covered,  resembling,  in  this  respect,  the 
tail  of  the  Jipus  canceriformis. 

This  fragment  of  an  Asaph  is  in  a  homogeneous, 
compact,  blackish  limestone,  which  contains  no 
other  kind  of  petrifaction.  I  know  not  where  it  was 
found.  It  is  in  the  cabinet  of  M.  de  Dree. 

On  plate  2  of  Professor  Brongniart's  work,  he  has 
given  figures  to  illustrate  this  species;  fig.  3  A.  re- 
presents the  whole  fragment,  and  3  B.  two  of  the  ribs 
of  the  lateral  lobes,  magnified  to  show  the  arrange- 
ment of  the  tubercles,  which  are  very  peculiar. 

From  the  above  description  it  will  be  readily  per- 
ceived, that  the  A.  Hausmanni  comes  very  near  to 
the  A.  Laticostatus.  There  are,  however,  many 
striking  differences,  which  will  be  obvious  to  those 
who  compare  our  cast  with  the  figures  of  Brong- 
niart.  The  shape  of  the  ribs,  and  the  tubercles  upon 
them;  the  form  of  the  middle  lobe  and  of  the  inter- 
stices between  the  articulations,  are  all  peculiar  to 
E  2 


54 

each.  The  elongation  of  the  tail  in  our  species  is 
alone  sufficient  to  distinguish  it.  We  have  always- 
been  doubtful  whether  the  minute  granulations  on 
our  species  were  not  produced  by  the  sandstone  in 
which  it  is  petrified. 

Upon  what  authority  the  A.  Hausmanni  has  been 
considered  as  a  species  belonging  to  the  United 
States  we  cannot  determine.  In  the  valuable  and  ex- 
tensive cabinet  of  trilobites  belonging  to  the  Albany 
Institute.,  there  are  a  number  of  specimens  labelled 
with  this  name  by  Professor  A.  Eaton.  If  we  mis- 
take not,  he  mentioned  to  us  that  similar  fragments 
of  this  fossil  were  sent  by  him  to  Brongniart,  who, 
we  understand,  is  the  author  of  the  list  of  trilobites 
found  in  the  manual  of  De  la  Beche.  The  specimens 
which  have  been  examined,  both  in  the  cabinet  of 
Professor  Eaton,  and  in  that  of  the  Albany  Institute., 
are  certainly  not  identical  with  the  figures  or  de- 
scriptions published  of  the  A.  Hausmanni.  Profes- 
sor Eaton,  in  his  Geological  Text  Book,  at  page  3K 
thus  describes  his  A.  Hausmanni: — "  Tail  rounded, 
and  forming  the  middle  of  a  circular  arc  whose  cen- 
tre is  in  the  fore  abdomen,  near  the  head;  covering 
tubercled  or  spined.  Found  in  coral  rag  on  the 
south  shore  of  Lake  Erie.  Also,  in  its  underlaying 
grit  slate  on  the  Helderberg."  Some  other  trilobites 
mentioned  in  De  la  Beche's  list  as  occurring  in  the 
United  States,  we  have  not  been  so  fortunate  as  to 
meet. 


55 


ASAPHUS  PLEUROPTYX.*     Cast  No.  IS. 

Corpore  depresso;  cute  coriacea  tuberculis  mini- 
mis;  costis  striatis;  cauda  acuta,  brevi. 

This  species  like  most  other  specimens  of  this 
genus,  in  our  cabinets,  is  decapitated — every  other 
part,  however,  appears  to  be  in  a  good  state  of  pre- 
servation. 

The  articulations  of  the  abdomen  and  tail,  which 
cannot  readily  be  distinguished  from  each  other,  are 
seventeen  in  number.  The  middle  lobe  is  flat,  and 
regularly  tapers  to  an  obtuse  lip;  it  is  marked  on 
each  side  with  longitudinal  impressed  lines  or  little 
grooves.  The  costal  arches  on  their  upper  side  have 
a  deep  and  narrow  channel,  running  through  their 
whole  course.  The  costal  arches  of  the  abdomen 
have  no  membranaceous  expansion  beyond  their  ter- 
minations; this  organization  is  only  visible  immedi- 
ately below  the  end  of  the  middle  lobe,  where  it  quick- 
ly finishes  in  an  acute  point.  A  large  portion  of  the 
crustaceous  shell  remains,  and  is  covered  with  dis- 
tinct granulations;  those  on  the  tail  are  the  least 
obvious. 

This  species  approaches  very  near  the  A.caudatus, 
but  the  grooves  on  the  middle  lobe,  the  smallness  of 
the  costal  arches,  and  the  limited  extent  of  the  mem- 
branaceous expansion  round  the  lower  portions  of 
the  shell,  will  sufficiently  distinguish  it. 

*  From  the  Greek  word  for  "  grooved  ribs." 


56 

Two  specimens  of  this  Asaph  are  in  the  cabinet  of 
the  Albany  Institute,  The  one  from  which  our  cast 
is  taken,  was  found  on  the  Helclerberg  mountains;  it 
is  embedded  in  a  light  grey  coloured  limestone  shale* 
The  other  specimen,  which  is  much  smaller,  was  dis- 
covered near  the  Genessee  river,  in  the  State  of  New 
York.  The  rock  in  which  it  occurs  is  identical  in 
its  constitution  with  the  other.  It  contains  other 
species  of  trilobites,  and  a  number  of  shells. 

ASAPHUS  MICRURUS.*     Cast  No.  19.     Fig.  3. 

Cauda  attenuata,  acuta;  corpore  valde  convexoj 
costis  striatisj  parte  marginal!  vix  membranacea. 

This  fine,  large  caudal  termination  of  an  Asaph  is 
in  the  cabinet  of  the  Albany  Institute — and  it  is  a 
subject  of  great  regret,  that  all  that  has  yet  been  dis- 
covered relating  to  this  highly  interesting  trilobite, 
is  to  be  seen  in  this  fragment. 

There  are  eighteen  articulations  of  the  tail  and 
abdomen,  which  cannot  be  distinguished  from  each 
other.  The  middle  lobe  is  composed  of  a  series  of 
straight,  distinct,  parallel  articulations,  very  convex 
about  the  middle,  so  as  to  form  a  kind  of  longitudinal 
ridge  down  the  back.  The  costal  arches  of  the 
lateral  lobes  are  very  distinct,  and  are  longitudinally 
striated  or  grooved  on  their  upper  surface,  particular- 
ly those  near  the  upper  part  of  the  animal.  The 
membranaceous  expansion  is  very  narrow  along  the 

*  From  the  Greek,  for  "  minute  tail." 


57 

sides  of  the  body,  and  forms  a  sort  of  hem;  below 
the  central  portion  of  the  tail  it  makes  a  short  acute 
projection,  which  seems  to  be  supported  by  a  short 
costal  elongation  of  the  middle  lobe.  Length  two 
inches  and  a  half. 

The  A.  Micrurus  was  found  in  the  black  foetid 
limestone  of  Trenton  Falls,  by  M.  H.  Webster,  Esq., 
and  by  him  placed  in  the  rich  collection  of  trilobites 
in  the  Albany  Institute.  The  limestone  in  which 
this  Asaph  is  embedded,  is  almost  one  entire  mass  of 
petrifactions.  The  general  aspect  of  the  A.  Micru- 
rus is  very  similar  to  that  of  a  calymene — but  judg- 
ing from  its  structure,  it  could  never  contract  its 
shell  into  a  spherical  figure.  Its  minute  tail,  and 
narrow  membranaceous  expansion  round  the  terminal 
edges  of  the  lateral  lobes  are  quite  peculiar,  and  de- 
termine it  to  be  an  Asaph. 

ASAPHUS  WETHERILLI.*     Green.     Cast  No.  20. 

Clypeo  postice  arcuato,  sulcato;  abdominis  articu- 
lis  duodecim;  cauda  vix  membranacea;  cute  corea- 
cea  vix  punctata. 

The  contour  of  this  beautiful  Asaph  is  very  regu- 
larly ovate;  unlike  most  of  the  remains  of  this  genus, 
the  buckler  is  still  attached  to  the  abdomen,  though 

*  I  have  named  this  species  in  compliment  to  my  friend,  John 
P.  Wetherill,  Esq.,  whose  magnificent  cabinet  of  fossils  in  the 
Academy  of  Natural  Sciences  of  Philadelphia,  will  ever  remain 
as  a  monument  of  his  discrimination,  enterprise,  and  liberality. 


58 

one  of  the  cheeks,  and  a  portion  of  the  front  are  ob- 
scured by  the  rock  in  which  the  animal  is  imbedded. 
The  cheeks  form  spherical  triangles.  The  oculife- 
rous  tubercles,  though  a  good  deal  defaced,  seem  to 
have  been  circular  and  not  lunate,  as  in  the  A.  Cau- 
datus.  A  raised,  curved  line  passes  from  and  over  the 
eye,  between  it  and  the  lateral  lobe  of  the  abdomen. 
The  central  lobe  of  the  back  is  composed  of  twelve 
double  joints,  and  that  of  the  tail  of  six  single  articula- 
tions; where  the  epidermis  or  shell  is  perfect,  all  the 
articulations  appear  single.  The  last  joint  of  the  tail 
is  longer  than  in  any  other  of  our  species.  The  ribs 
of  the  abdomen  are  rather  broad,  and  have  a  deep 
furrow  scooped  out  along  their  upper  surface;  their 
extremities,  where  they  can  be  discovered,  are  de- 
tached from  each  other,  and  terminate  in  reflected 
points,  like  those  of  the  A.  Limulurus.  The  costal 
arches  of  the  tail  are  delicately  grooved,  and  termi- 
nate in  the  membrane.  The  membranaceous  expan- 
sion round  the  edge  of  the  tail  is  very  narrow,  and 
appears  to  form  no  projection  beyond  its  central 
part.  The  whole  epidermis  is  finely  marked  with 
granulations.  Length  one  inch  and  three-fourths— 
breadth  one  inch  and  one-fourth. 

This  interesting  species  was  found  in  limestone 
shale,  near  Rochester,  in  Munroe  County,  N.  Y.j  and 
is  now  in  the  valuable  cabinet  of  the  Albany  Institute. 
An  accidental  fissure  of  the  rock  disclosed  not  only  a 
fine  specimen  of  both  the  mould  and  the  cast  of  this 
animal,  but  also  another  individual  of  the  same  spe- 
cies in  contact  with  it.  From  the  peculiar  attitude 


59 

which  these  fossilized  animals  maintain  towards  each 
other,  they  appear  to  have  been  combatants  at  the 
very  moment  when  the  catastrophe  occurred  which 
produced  their  mineralization*  In  the  Museum  of 
the  Garden  of  Plants  at  Paris,  there  is  a  large  speci- 
men of  two  fossil  fish,  which  are  supposed  by  many 
to  have  been  destroyed  and  covered  with  mineral 
matter,  when  one  of  them  was  in  the  very  act  of 
swallowing  the  other.  Mr.  Bake  well,  however,  who 
accurately  examined  this  specimen,  is  of  opinion, 
that  the  two  heads  of  the  fish  had  been  pressed  to- 
gether by  the  superincumbent  weight. 

GENUS  PARADOXIDES.     Brongniart. 

The  animals  arranged  under  this  generic  name,  in- 
clude the  organic  remains  described  by  Linne  as  En- 
tomolithus  paradoxus,  and  Brongniart  has  given  the 
specific  appellation  which  the  great  Swedish  natural- 
istappliedto  thesesingular  animals,  out  of  compliment 
to  him,  though  he  considers  it  quite  inappropriate. 
The  late  Professor  Dalman  calls  this  genus  Olenus, 
and  quotes  Paradoxides  as  a  synonyme,  but  the  term 
of  Brongniart  seems  to  have  the  priority,  and  there- 
fore must  be  preferred. 

The  animals  belonging  to  the  Paradoxides  have  the 
body  very  much  depressed,  and  the  lateral  much 
wider  than  the  middle  lobe. 

The  buckler  is  nearly  semicircular,  the  cheeks  are 
destitute  of  eyes,  and  the  front  is  marked  with  three 


60 

transverse  furrows.  This  last  character  is  probably 
not  a  permanent  one. 

But  the  most  distinguishing  character,  is  the  pro- 
longation of  the  costal  arches,  particularly  those  of 
the  tail,  beyond  the  membrane  which  they  are  sup- 
posed to  support;  the  termination  of  these  arches  is 
in  teeth  or  spines.  Some  species  of  the  Asaph  have 
prolongated  extremities  to  the  ribs  of  the  abdomen, 
but  we  have  never  seen  them  on  the  arches  of  the  tail* 

This  genus  is  said  to  comprise  a  great  number  of 
species,  but  the  only  one  found  in  North  America,  as 
far  as  our  knowledge  extends,  is  that  described  by 
J.  J.  Bigsby,  in  the  fourth  volume  of  the  Journal  of 
the  Academy  of  Natural  Sciences  of  Philadelphia. 
As  we  have  not  seen  the  specimen,  we  add  the  de- 
scription of  it  in  the  author's  own  words. 

PARADOXIDES  BOLTONI.     Bigsby.     Figure  5. 

Oval,  blind;  surface  with  small  tubercles  and 
striae;  clypeus  rounded  before;  exterior  angle  ex- 
tending in  a  broad  spine;  abdomen  fourteen  jointed; 
segments  recurved,  falcate;  tail  membranaceous  and 
serrate. 

The  shape  of  this  individual  is  oval,  approaching 
ovate;  it  is  moderately  flat;  the  whole  length  is  five 
inches  and  four-fifths;  its  breadth  across  the  middle 
is  four  inches  and  nine-tenths;  wherever  the  cutis  is 
not  removed,  it  is  covered  profusely  and  irregularly 
with  small  tubercles.  The  denuded  portions  in  this 
specimen,  for  the  space  of  three  quarters  of  an  inch 


61 

from  the  external  margin,  is,  in  a  very  small  degree, 
depressed,  and  displays  a  number  of  broken  and  con- 
tinuous strise,  parallel  to  that  margin.  There  are  no 
traces  of  organs  of  vision.  The  buckler  is  nearly  the 
segment  of  a  circle;  anterior  edge,  in  the  present 
case,  imperfect;  it  is  four  inches  and  three-fifths 
broad,  and  one  inch  and  one-ninth  long  at  the  centre; 
it  joins  the  abdomen  by  a  somewhat  sinuous  trans- 
verse line;  cheeks  and  front  of  equal  breadth;  the 
former  are  flat,  but  rise  at  the  sharp  ridge  by  which 
they  unite  with  the  front;  they  are  triangular  in 
shape;  their  outer  angles  terminating  by  an  acute 
tip.  The  striae  mentioned  above  are  here  not  quite 
parallel  to  the  external  border;  the  front  is  a  shallow 
depression;  rounded  but  tapering  anteriorly;  it  is  in- 
tersected from  above  on  each  side  obliquely  towards 
the  mesial  line,  by  a  ridge  bifurcating  downwards; 
another  smaller  ridge  nearly  bisects  the  front  perpen- 
dicularly. 

The  abdomen  and  post  abdomen  are  not  distinct. 
The  abdomen  exclusive  of  the  cauda  is  three  inches 
and  a  half  long;  it  exhibits  fourteen  costae  varying 
indiscriminately  from  one-fifth  to  one-fourth"  of  an 
inch  in  breadth,  except  the  three  inferior  ones,  which 
are  rather  broader;  they  occupy  the  -whole  abdomen 
without  nnembranaceous  interspaces,  and  are  sepa- 
rated by  a  black  sulcus,  not  always  well  defined,  and 
sometimes  a  line  in  diameter.  Each  costa  is  canali- 
culated  from  the  upper  and  under  angle  to  the  tip. 

The  middle  lobe  is  separated  from  the  lateral  by  a 
shallow,  rude  sulcus,  which  however,  does  not  al- 


62 

ways  destroy  the  continuity  of  the  costse,  as  they  cross 
it;  this  lobe  is  slightly  convex,  one  inch  and  a  half 
broad  at  the  top,  and  so  continues  to  the  sixth  costa, 
after  which  it  gradually  contracts,  until  at  the  bot- 
tom it  is  one-fifth  of  an  inch  broad,  subsiding  insensi- 
bly into  a  flat  membrane-like  surface;  its  longitudi- 
nal sulci  pass  one  inch  farther  downwards,  and  ex- 
panding a  little,  unite  with  the  costas  on  each  side  the 
posterior  edge  of  the  space  included  by  them,  being 
dentated. 

The  lateral  lobes  are  quite  flat,  one  inch  and  a  half 
broad  anteriorly,  and,  by  gradual  prolongation,  be- 
come at  the  fourth  costa  one  inch  and  four-fifths  in 
breadth;  this  dimension  is  maintained  to  the  ninth 
articulation,  when  it  slowly  decreases  to  one  inch  at 
the  bottom;  the  recurvature  of  the  costae  is  gentle  in 
the  upper  eight,  but  then  decreases  rapidly.  Their 
extremities,  advancing  two-fifths  and  four-fifths  of  an 
inch  into  the  embedding  rock,  are  falcate  with  their 
raised  black  edges,  and  clearly  marked  points. 

This  trilobite  was  found'  by  Lieut.  Bolton,  at  Lock- 
port,  in  the  state  of  New  York,  in  the  black,  shaly, 
horizontal  limestone  forming  the  lower  part  of  the 
ravine  by  which  the  Erie  canal  ascends  the  parallel 
ridge  of  Lake  Ontario.  Dr.  Bigsby  remarks  on  this 
locality,  "  I  am  not  prepared  to  assign  to  this  lime- 
stone its  exact  place  in  the  series  of  geological  for- 
mations; it  is  above  the  saliferous  sandstone,  and 
therefore  more  recent  than  the  rocks  best  known  as 
abounding  in  trilobites."  We  have,  therefore,  in  this 
instance,  another  fact,  which  demonstrates  that  blind 


63 

trilobites  are  not  Confined ,  to  a  geological  period 
more  remote  than  That  which  has  produced  the  ani- 
mals with  oculiferous  tubercles. 

GENUS  OGYGIA.     Brongniart. 

In  the  vast  quarries  of  slate  at  Angers,  in  France, 
there  is  frequently  noticed  two  very  remarkable  or- 
ganic remains,  which  have  for  a  loic^  time  excited  the 
attention  of  naturalists.  To  receive  these  curious 
relics,  Professor  Brongniart  established  the  genus, 
Ogygia,  which  he  thus  characterizes.  Body  much 
depressed — elongated  into  an  ellipse,  terminated  in 
points — nearly  equal  at  its  extremities,  and  not  capa- 
ble of  contracting  itself  into  a  spherical  form.  The 
buckler  is  bordered  by  a  slight  longitudinal  furrow, 
rising  from  its  anterior  extremity,  and  its  posterior 
angles  terminating  in  elongated  points.  The  abdo- 
men has  eight  articulations,  and  its  longitudinal  lobes 
are  not  very  prominent.  The  eyes  are  neither  promi- 
nent nor  reticulated  and  there  are  no  other  protube- 
rances on  the  buckler. 

In  Professor  Brongniart's  original  work  on  theTri- 
lobites,  he  has  described  the  two  specimens  from 
Angers,  under  the  specific  names  of  Guettardi,  and 
Desmarestii,  in  compliment  to  M.  M.  Guettard  and 
Desmarest;  and  in  De  La  Beche's  Manual  of  Geolo- 
gy, we  are  informed  that  he  has  since  identified  two 
other  species;  one  of  which  is  supposed  to  be  found 
in  North  America;  this  he  calls  Ogygia  Sillimani; 
the  banks  of  the  Mohawk  River,  near  Schenectady, 


64 

is  the  locality  from  which  it  is  said  to  have  been  de- 
rived. * 

As  we  have  not  been  able  to  find  any  detailed  ac- 
count of  this  species,  we  have  admitted  both  it  and 
the  genus  to  which  it  is  said  to  belong  into  our  Mo- 
nograph exclusively  on  the  high  authority  of  Profes- 
sor Brongniart,  as  quoted  in  the  Manual  of  Geology. 
We  are  not  ignorant  of  the  species  of  Trilobites  found 
near  Schenectady,  and  if  permitted  to  offer  a  sugges- 
tion on  this  subject,  it  would  be,  that  the  description 
of  the  American  ogygia,  was  made  out  by  its  distin- 
guished author  from  the  fragment  of  an  Isotelus. 
The  Isotelus  is  not  uncommon  in  that  vicinity,  and 
one  of  its  extremities  might,  even  by  a  very  close 
observer,  be  mistaken  for  that  of  an  Ogygia — espe- 
cially by  those  who  are  not  perfectly  familiar  with 
the  Isotelus. 

GENUS  ISOTELUS.     Dekay. 

This  fine  genus  of  trilobites  was  established  No- 
vember, 1824,  by  my  friend  James  E.  Dekay,  M.  D. 
It  embraces  a  considerable  number  of  species  so 
analogous  to  each  other,  that  except  in  a  very  few 
cases,  it  is  exceedingly  difficult  to  point  out  their  dis- 
tinctive characters.  Some  of  the  species  of  Isotelus, 
appear  to  have  reached  a  greater  size  than  any  other 
trilobite.  In  the  cabinet  of  P.  A.  Browne,  Esq.,  there 
is  the  fragment  of  one,  which  must  have  been  four- 
teen or  fifteen  inches  long. 

The  Isotelus  is  found  in  several  parts  of  North 


65 

America,  but  most  abundantly  in  the  black  transition 
limestone,  in  the  northern  section  of  the  country. 
The  richest  locality,  not  only  of  this  genus,  but  also 
of  the  Calymene  and  the  Asaph,  is  Trenton  Falls, 
on  West  Canada  Creek,  about  1 3  miles  to  the  north 
of  Utica,  in  the  state  of  New  York.  The  following 
extracts  from  the  notes  of  Professor  Renwick,  which 
accompany  Dr.  Dekay's  account  of  the  Isotelus,  will 
give  some  idea  of  this  vast  depository  of  the  medals 
of  ancient  zoology.  West  Canada  Creek,  is  one  of 
the  principal  branches  of  the  Mohawk  River.  At 
Trenton  Falls  it  has  worn  itself  a  passage  through 
the  rock  for  the  distance  of  nearly  two  miles,  forming 
a  series  of  water  falls;  and  has  thus  laid  open  to  view 
the  strata  to  the  depth  of  probably  300  feet.  The 
layers  of  the  rock  thus  disclosed  are  nearly  hori- 
zontal, and  of  various  thicknesses:  they  are  composed 
of  limestone,  with  the  exception  of  numerous  thin 
veins  of  argillaceous  matter.  The  higher  strata  are 
composed  of  carbonate  of  lime  nearly  pure,  of  a  light 
grey  colour  and  crystalline  structure.  At  greater 
depths  it  is  more  compact  and  darker  in  colour,  and 
finally  it  appears  quite  black  and  highly  foetid.* 

Animal  remains  are  contained  in  every  part  of  the 
rock;  besides  several  genera  of  trilpbites,  we  have 
several  species  of  orthocera.  Encrinites  and  Fun- 
gites — Nautili — Terebratulse  and  Producti,  are  quite 
common.  The  favosites  here  are  sometimes  six 
inches  in  diameter,  and  in  such  numerous  columns, 

*  See  Annab  of  N.  Y.  Lyceum,  vol.  i.  page  185. 
F  2 


66 

as  to  have  induced  the  late  worthy  proprietor  of  this 
interesting  spot,  Mr.  J.  Sherman,  to  consider  them 
as  analogous  in  structure  to  the  basaltic  columns  of 
Staffa  and  the  Giant's  Causeway;  he  therefore  main- 
tains the  extravagant  theory  that  these  columns  are 
nothing  more  than  gigantic  favosites.*  We  visited 
this  famous  locality  of  trilobites  not  long  since,  and 
were  almost  as  much  delighted  with  the  sublimity 
and  grandeur  of  the  cataract,  and  the  picturesque 
and  romantic  character  of  the  glen,  as  with  the  re- 
liques  of  olden  times,  which  are  scattered  here  in 
such  profusion. 

The  genus  Isotelus,  derived  from  /V<j$,  equal,  and 
TgAo$,  extremity,  is  thus  characterized  by  Dr.  Dekay. 

Body  oval — often  contracted,  not  unfrequently  ex- 
tended. 

Head  or  buckler  large  and  rounded,  equalling  the 
tail  in  size,  but  with  two  oculiform  tubercles. 

Jlbdomen  with  eight  articulations. 

Frontal  process  beneath,  with  two  semilunar  termi- 
nations. 

Post  abdomen  or  tail,  broad,  expanded  with  indis- 
tinct divisions,  as  large  as  the  buckler. 

Longitudinal  lobes  very  distinct. 

Other  distinguishing  marks  by  which  this  genus 
may  be  known,  have  been  given  in  our  introduction. 

*  See  a  Description  of  Trenton  Falls,  by  John  Sherman,  p.  17. 


67 


ISOTELUS  GIGAS.    Defray.     Casts  Nos.  21  and  22. 

Head  representing  a  spherical  triangle,  surface 
punctate,  convex,  descending  from  between  the  eyes 
to  the  anterior  border,  which  has  a  narrow  raised 
rim;  posterior  extremity  concave  and  corresponding 
to  the  articulation  of  the  abdomen.  Eyes  elevated, 
prominent,  sub-pedunculated;  cornea  oblong,  lunated, 
highly  polished  $  abdomen  with  eight  distinct  arti- 
culations, the  middle  lobe  double  the  size  of  the  late- 
ral one  :  these  latter  are  continuous  with  the  middle 
lobe,  have  a  deep  furrow  impressed  on  their  upper 
surfaces,  which  becomes  gradually  effaced  towards 
their  narrow  free  extremities.  These  lateral  lobes 
are  rounded  at  their  extremities,  and  flattened  in  such 
a  manner  as  to  allow  each  lobe  to  slide  easily  under 
the  lobe  immediately  preceding.  Tail  subtriangular, 
convex,  equalling  the  head  in  size,  with  the  posterior 
termination  rounded.  On  the  centre  of  its  surface, 
when  accidentally  decorticated,  a  slight  elevation 
may  be  traced,  if  the  specimen  be  held  in  a  certain 
light,  which  appears  to  be  a  continuation  of  the  mid- 
dle lobe;  this  extends  to  within  a  short  distance  of 
the  posterior  angle  of  the  tail,  when  it  is  either  en- 
tirely effaced  or  terminates  in  an  abrupt  truncation. 
Another  elevation  runs  parallel  to  and  at  a  short  dis- 
tance from  the  edge  of  the  tail.  These  elevations 
are  connected  by  obscure  parallel  lines,  imitating 
the  spaces  between  the  lateral  lobes.  When  the  tail  is 
fractured  on  the  borders,  a  semilunar  depression  is 


68 

visible,  exhibiting  concentric  stria*.  The 'whole  Sur- 
face of  the  animal  has  a  jet  black  polish.  Length 
from  6  to  12  inches. 

The  original  of  our  cast  is  in  the  cabinet  of  J.  P. 
Wetherill,  and  was  found  near  Cincinnati,  Ohio.  It  is 
of  a  yellowish  colour,  and  occurs  in  argillaceous  slate. 
Specimens  are  common  in  most  cabinets  of  Ameri- 
can fossils.  The  Lyceum  in  New  York,  possesses  a 
fragment  of  an  individual  of  this  species,  which  must 
have  been  at  least  17  inches  long.  Our  cast,  No.  22, 
is  from  the  gigantic  tail  in  the  cabinet  of  P.  A.  Brown, 
Esq.  Mr.  Stokes  describes  the  I.  gigas  as  a  new 
species  under  the  name  of  Asaphus  Platycephalus,  in 
Geolog.  Trans,  vol.  i.  N.  Scries.  His  specimen  was 
found  in  the  limestone  of.  St.  Joseph's,  Canada. 

ISOTELUS  PLANUS.*     Dekay.     Cast  No.  23. 

Head  more  rounded  than  the  preceding,  and  less 
elevated.  Tail  flat,  rounded.  Total  length  two  inch- 
es and  one-tenth.  Breadth  one  inch  and  one-tenth. 
Length  of  the  head,  six-tenths — of  the  abdomen, 
eight-tenths,  and  of  the  tail  seven-tenths. 

Dr.  Dekay  is  of  opinion  that  this  species  may  pos- 
sibly prove  to  be  the  young  of  the  preceding.  The 
relative  proportions  of  its  buckler  and  tail  vary 

*  The  general  usage  of  naturalists  is  to  prefix  a  short  Latin 
caption  to  the  species  which  they  discover — but  as  some  authors 
do  not  follow  this  fashion,  we  are  satisfied  to  suffer  their  descrip- 
tions to  stand  without  it.  We  believe,  indeed,  that  the  time  is 
not  very  distant,  when  every  author  will  be  expected  to  publish 
his  discoveries  in  his  vernacular  tongue. 


69 

considerably  from  those  of  the  I.  gigas;  and  the 
depth  of  the  lateral  lobes,  which  exceeds  three-tenths 
of  an  inch,  would  almost  of  itself  determine  it  to  be 
a  new  species.  The  original,  from  which  our  cast 
was  taken,  is  in  the  cabinet  of  J.  P.  Wetherill.  It 
was  found  near  Newport,  Kentucky,  and  occurs  in 
argillaceous  slate.  The  fossil  is  of  a  dirty  yellow 
colour. 

ISOTELUS  CYCLOPS.*    Green.     Cast  No.  24.  Fig.  7. 

Clypeo  antice  attenuate,  piano;  oculis  rotundis, 
proximis;  cauda  ovata,  acuminata. 

The  head  of  this  species  is  much  more  elongated 
than  it  is  in  the  two  preceding  species.  The  anterior 
portion  of  the  buckler  is  much  prolonged.  The  eyes 
are  approximate,  rounded,  and  near  the  posterior 
edge  of  the  head.  The  abdomen  is  furnished  with 
eight  distinct  articulations;  the  middle  lobe  is  scarce- 
ly broader  than  the  lateral  lobes;  tail  rather  broader 
than  the  head,  and  ovate;  posterior  termination  more 
rounded  than  the  buckler.  Length  nearly  three  inches. 

The  specimen  from  which  our  model  was  taken 
belongs  to  the  Albany  Museum.  No  label  is  attach- 
ed to  it,  but  I  was  informed  by  Mr.  Meach,  one  of 
the  proprietors,  that  it  was  found  in  the  western  part 
of  the  State  of  New  York.  It  is  embedded  in  an  ash- 
coloured  limestone.  The  specimen  is  a  good  deal 
worn — but  the  peculiar  form  of  the  eyes,  and  the  nar- 

*  From  the  Greek  for  "  round  eyes," 


70 

rowness  of  the  middle  abdominal  lobe,  clearly  distin- 
guish it  from  either  of  Dr.  Dekay's  species. 

ISOTELUS  MEGALOPS.*    Green.    Cast  No.  25. 

Clypeo  antice  subrotundato,  postice  arcuato;  oculis 
magnis,  rotundis,  eminentissimis;  caucla  suborbicu- 
lari,  limbo  latoj  articulis  abdominis  octo. 

The  buckler  in  its  contour  resembles  very  much 
the  head  of  the  I.  gigasj  it  is,  however,  rather  more 
rounded  before,  and  arcuated  behind.  The  oculi- 
ferous  tubercles,  are  very  peculiar,  being  very  large, 
round,  and  exceedingly  prominent.  They  have  a 
good  deal  the  appearance  of  solid  hemispheres 
placed  on  the  forehead  of  the  animal.  They  are  ex- 
actly on  a  line  with  the  two  abdominal  furrows.  The 
abdomen  is  composed  of  eight  distinct  articulations; 
the  middle  lobe  is  rather  larger  than  the  lateral 
lobes.  The  tail  is  suborbicular,  convex,  and  rather 
less  than  the  head.  Length  nearly  five  inches. 
Breadth  almost  three  inches. 

This  magnificent  Isotelus  was  obtained  near  Tren- 
ton falls,  in  New  York,  by  P.  A.  Browne,  Esq.,  and 
now  forms  a  part  of  his  fine  collection  of  fossils,  in 
this  city.  It  occurs  in  black  transition  limestone. 
It  differs  essentially  from  the  I.  gigas  of  Dekay,  in 
the  magnitude,  collocation,  and  contour  of  the  eyes. 
Those  of  the  I.  gigas  are  oblong  and  lunate,  and 
nearly  half  the  distance  between  the  anterior  and  the 

*  From  the  Greek  for  "  great  eyes." 


71 

posterior  edges  of  the  buckler;  those  of  the  I.  Me- 
galops  are  not  only  much  larger,  but  they  are  round, 
and  very  near  the  posterior  border  of  the  head. 


ISOTELUS  STEGOPS.*     Green.     Casts  Nos.  26  and  27. 

Clypeo  antice,  caudaque  postice  attenuatis;  cute 
coreacea  punctis  minimis. 

The  head  of  this  species  is  nearly  in  the  form  of  a 
spherical  triangle;  its  anterior  edge  is  vertically  flat- 
tened all  round,  but  does  not  produce  a  narrow  raised 
rim,  such  as  is  described  by  Dr.  Dekay,  to  belong  to 
the  I.  gigas.  The  eyes  are  prominent,  and  rather 
nearer  the  lateral  edge  of  the  buckler,  than  to  its  pos- 
terior border.  The  shell  of  the  buckler  forms  a  re- 
markable projection  over  the  top  of  each  oculiferous 
tubercle,  something  like  an  eye-lid.  Continuous 
with  the  edge  of  this  cuticular  projection,  there  is  a 
curved  linear  depression,  which  terminates  on  both 
sides,  at  the  edge  of  the  buckler.  This  kind  of 
suture,  though  remarkably  developed  in  this  species, 
is  not  peculiar  to  it,  being  more  or  less  distinct  in 
most  of  the  Isoteli.  The  articulations  of  the  abdo- 
men are  lost;  there  can  be  little  doubt,  however,  that 
they  were  eight  in  number.  The  tail  is  subtriangu- 
lar,  and  less  in  magnitude  than  the  buckler. 

This  fossil  is  among  the  number  of  fine  specimens 
in  the  cabinet  of  J.  P.  Wetherill.  It  is  in  a  rolled  or 

*  From  two  Greek  words,  which  signify  "  covered  eyes." 


72 

contracted  attitude,  and  is  somewhat  distorted.  We 
have  given,  however,  models  of  the  head  and  the  tail, 
in  two  distinct  pieces.  The  external  shell,  or  calca- 
reous covering,  is  more  perfect  in  this  specimen 
than  in  any  other  we  have  ever  seen.  A  considera- 
ble portion  of  the  under  side  of  the  anterior  part  of 
the  buckler,  is  also  well  preserved,  and  perfectly  co- 
incides with  the  figure  and  description  given  of  it  by 
Dr.  Dekay  and  Mr.  Stokes.  There  is  another  frag- 
ment of  an  Isotelus  in  the  cabinet  of  Mr.  Wetherill, 
showing  eight  articulations  of  the  abdomen,  which 
probably  belongs  to  another  individual  of  this  spe- 
cies. The  dorsal  shell  is  in  a  high  state  of  preser- 
vation. This  species  is  embedded  in  clay  slate,  and 
was  found  in  Newport,  Kentucky. 

GENUS  CRYPTOLITHUS.     Green. 

Among  the  numerous  organic  relics  embedded 
in  black  limestone  at  Trenton  Falls,  in  the  State  of 
New  York,  there  is  often  found  the  fragment  of  a  tri- 
lobite  which  cannot  properly  be  referred  to  any  of 
the  genera  already  mentioned.  Dr.  J.  Bigsby,  in  his 
Sketch  of  the  Geology  of  the  Island  of  Montreal,  has 
figured  and  described  a  fossil  which  occurs  at  that 
place,  which  approaches  in  its  specific  characters  to 
the  fragments  found  at  Trenton — but  he  does  not 
suggest  for  his  relic  any  name.  Professor  Brong- 
niart  has  also  represented,  plate  4,  figs.  5  and  7  A. 
B.  C.,  the  fragments  of  trilobites  from  Russia  and 
from  Llandillo,  in  Wales,  which  seem  to  differ  but 


73 

little  from  those  above  noticed,  these  are  also  with- 
out names.  Under  such  circumstances,  we  have 
thought  it  expedient  to  group  these  relics  under 
the  generic  term  of  Cryptolithus,  a  name  analogous 
to  Calymene,  Asaphus,  Ogygia,  and  Agnostus,  and 
which  may  with  propriety  be  applied  to  the  animal, 
should  it  ever  be  discovered  entire.* 

Body,  contractile. 

Buckler,  lunate,  convex,  outer  edge  surrounded  by 
a  semicircular,  reticulated,  or  tessellated  border. 

Front  or  middle  lobe  of  the  buckler  very  protube- 
rant. 

Oculiferous  protuberances,  none. 

Abdomen,  much  compressed,  trilobate. 

CRYPTOLITHUS  TESSELLATUS.     Green.     Cast  No.  28, 
and  Fig.  4. 

Clypeo  rotundato,  fronte  valde  convexo,  capite  an- 
tice  semicircular!  margine  tessellato  ornato. 

Outline  of  the  buckler  hemispherical,  the  edge  sur- 
rounded by  a  semicircular  border  of  tessellated  or 
rounded  punctures,  in  three  concentric  rows  in  front 
— on  each  side  near  the  posterior  angle  of  the  buck- 
ler, these  rows  of  punctures  are  more  numerous^ 
the  front  is  highly  convex;  is  rounded  before,  and 

*  Since  the  above  was  written,  and  the  C.  Tessellatus  pub- 
lished, I  have  received  a  fine  specimen  of  this  trilobite  from  Pro- 
fessor Eaton,  in  an  almost  perfect  state,  so  that  the  entire  ani- 
mal can  now  be  described. 

G 


74 

gradually  tapers  towards  the  abdomen.  The  cheeks 
form  spherical  triangles,  and  are  entirely  destitute  of 
oculiferous  tubercles  or  any  other  markings;  their 
posterior  angles  project  beyond  the  sides  of  the  ab- 
domen. Abdomen  and  tail  very  much  compressed, 
and  composed  of  about  ten  articulations;  costal  arches 
of  the  lateral  lobes  grooved^  tail  attenuated.  Whole 
length  half  an  inch. 

The  Cryptolithus  Tessellatus,  resembles  a  good 
deal  the  Entomostracites  Granulatus  of  Wahlenberg, 
and  which  Dr.  D  aim  an  calls  Asaphus  Granulatus. 
The  figure  of  this  animal  given  by  Brongniart,  table 
3,  fig.  7,  appears  to  be  quite  imperfect,  and  is  very  un- 
like, except  in  the  buckler,  the  representation  of 
Wahlenberg's  fossil,  given  by  Dalman,  table  2,  fig. 
6.  Though  the  angles  of  the  buckler  in  the  Asaphus 
Granulatus  are  much  more  elongated  than  those  of 
the  C.  Tessellatus,  it  may  perhaps  be  another  species 
of  the  same  genus.* 

*  The  following,  is  Dr.  Dalman's  description  of  the  Asaphus 
Granulatus : — 

A.  trunco  sexarticulato  pygidioque  laevibus,  capite  antice  se- 
micirculari  margine  granuloso,  angulis  posticis  extensis  corpore 
longioribus. 

Animalculum  singulare,  inversum  si  inspicitur,  lyram  forma 
fere  similans.  Caput  antice  semicirculare,  margine  distincto, 
serie  submoniliformi  e  granulis  approximatis  ornato,  discus  capitis 
laevis,  sed  ambitus  intra  marginem  punctis  elevatis  obsitus.  Hie 
ambitus,  una  cum  margine,  truncum  quoque  amplecti  videtur,  ad 
pygidii  basin  usque,  ubi  in  cornua  Icevia,  trunco  multo  longiora, 
abit.  Glabella  antice  fere  clavaRformis,  ad  basin  utrinque  emit- 
tens  lobi  rudimentum.  Truncus  brevis  Icevis  segmentis  constaris 


75 

The  animal  described  and  figured  by  Dr.  J.  Bigsby, 
to  which  we  have  already  referred,  seems  rather 
different  from  our  species.  His  specimens  were 
found  at  Montmorenci,  near  Quebec,  (Canada)  more 
than  an  inch  and  a  half  in  diameter.  The  following 
are  his  remarks  on  this  trilobite.*  "  The  front  of 
the  buckler  is  remarkably  convex,  and  has  on  each 
side  near  the  base,  three  very  small  transverse  lines, 
scarcely  to  be  called  depressions,  corresponding  to 
the  sulci  so  strongly  marked  in  the  genus  Calymene. 
There  is  frequently,  but  not  universally,  a  very  minute 
pisiform  process  on  the  centre  of  the  front.  The 
whole  upper  edge  of  the  buckler  is  always  surround- 
ed by  a  very  ornamental  semicircular  border,  some- 
times semi-elliptical,  of  punctures  placed  in  the 
meshes  of  a  net-work  in  high  relief  and  arranged 
close  together,  in  rays,  passing  perpendicularly  from 
the  buckler  and  forming  at  the  same  time  when  ob- 
served transversely,  curved  lines  parallel  to  its  upper 
rim  or  edge,  excepting  at  the  sides,  where  they  di- 
verge, leaving  a  space  occupied  by  other  lines  of  dot- 
tings,  parallel  to  the  former,  but  speedily  terminat- 
ing on  the  cheeks  of  the  buckler.  The  lines  which 

tantummodo  sex,  rhachide  angusta.  Pygidium  breve,  rotun- 
datum,  Iffive ;  adeo  parvum  ut  ne  quidem  capitis  disco  respondeat. 

Obs. — Oculos  atque  suturam  facialem  ex  autopsia  describere 
licet. 

Vide  Om.  Palseaderna  eller  de  sa  kallade  Trilobiterna  af. 
J.  W.  Dalman,  pages  50 — 4. 

*  See  Geology  of  the  Island  of  Montreal,  in  Lyceum  of  Nat. 
History,  N.  Y.  p.  214. 


76 

are  complete  from  side  so  side,  are  four  in  number. 
The  imperfect  additional  ones,  vary  from  two  to 
four;  the  smallest  and  inner,  consisting  only  of  two 
or  three  punctures.  A  plain  edging  includes  the  se- 
micircle of  punctures.  In  the  beds  of  these  casts, 
the  places  of  the  punctures  are  shown  by  small  coni- 
cal elevations,  and  those  of  the  ridges  of  the  net-work, 
by  corresponding  depressions." 

Should  this  prove  to  be  a  distinct  species,  we  pro- 
pose to  call  it  Cryptolithus  Bigsbii. 

The  Nuttainia  Concentrica  of  Professor  Eaton  seems 
also  very  nearly  allied  to  this  species;  he  describes 
it  as  having  "  four  or  five  concentric  arcs  of  punc- 
tures in  front  of  the  buckler,  separated  by  alternating 
arc1fc>f  fine  elevated  ridges."  The  genus  Nuttainia, 
to  •vpiich  he  refers  this  species,  cannot  include  it, 
and  the  N.  Sparsa;  for  these  two  relics  have  scarce- 
ly a  single  essential  character  in  common;  we  have, 
therefore,  confined  the  genus  Nuttainia,  to  the  spe- 
cies which  he  calls  Sparsa. 

The  Cryptolithus  Tessellatus  is  very  common  at 
Trenton  falls.  In  the  transition  limestone  at  Glenn's 
falls,  in  the  state  of  New  York,  during  a  very  short 
visit  to  this  place,  Dr.  R.  Harlan  procured  a  large 
number  of  this  fossil,  but  only  the  buckler,  the 
projecting  front  of  which  exhibited  a  pisiform  pro- 
tuberance above  the  level  of  the  strata.  Mr. 
Eaton  says  that  the  N.  Concentrica  "  occurs  in  the 
wacke  variety  of  transition  of  argillite,  on  the  Cham- 
plain  canal,"  between  the  town  of  Waterford  and  the 


77 

Mohawk  river.     The  specimen  in  my  cabinet,  from 
which  our  cast  was  made,  is  from  that  place. 

The  Cryptolithus  Tessellatus  occurs  also  in  the 
limestone  which,  according  to  Dr.  Bigsby,  overlays 
the  sandstone  in  the  island  of  Montreal.  At  most  of 
its  localities,  it  is  associated  with  the  Isotelus,  the 
Calymene,  and  with  several  species  of  Asaphus.  The 
Cryptolithus,  which  is  entirely  destitute  of  eyes,  being 
thus  found  with  the  oculiferous  species,  is  an  inte- 
resting fact,  and  controverts  the  opinion  of  Professor 
Wahlenberg,  that  the  trilobites,  which  are  without 
eyes  belong  to  a  geological  epoch  more  ancient  than 
those  which  are  furnished  with  oculiform  tubercles. 
That  organic  remains  furnish  us  with  the  most  satis- 
factory evidence  of  the  identity  or  dissimilarity  of 
certain  formations,  is  a  disputed  point  with  some 
geologists*  It  cannot  reasonably  be  doubted,  that 
new  and  isolated  facts  have  been  made  the  basis  of  a 
too  hasty  generalization.  On  this  subject  Count 
Rasoumowsky  makes  the  following  remarks: — "  Les 
divers  gisemens  des  Trilobites  ne  me  semblent  pas 
non  plus  pouvoir  etre  determines  avec  quelque  pre- 
cision. M.  Brongniart  parait  admettre  que  les  trilo- 
bites aveugles  ne  se  trouvent  que  dans  de  tres  an- 
ciennes  formations  dans  des  schistes  et  des  calcaires 
de  transitions;  mais  nous  avons  clonne  la  descrip- 
tion d'un  trilobite  [without  eyes]  des  bords  de  la 
Yaousa  pres  de  Moscow,  qui  n'appartient  certaine- 
ment  pas  aux .  formations  de  transition,  ce  qui  me 

*  See  Eclectic  Review,  for  July,  1832. 
G  2 


78 

donne  lieu  de  croire  que  cle  nouvelles  recherches  et 
cle  nouvelles  observations,  prouveront  qu'il  n'est  pas 
strictement  vrai  qu'en  France,  en  Angleterre,  en 
Russie,  il  n'existe  point  de  trilobites  entierement  prives 
d'yeux,  comme  le  dit  le  savant  auteur  que  je  viens 
de  citer."  See  Annales  des  Sciences  Naturelles, 
Vol.  8.  page  195* 

GENUS  DIPLEURA.     Green. 

Body,  contractile,  not  much  depressed,  and  slightly 
tapering. 

Buckler,  pustulous,  trilobate,  cheeks  protuberant, 
with  oblique,  annular,  oculiferous  tubercles. 

Abdomen,  with  fourteen  arliculations,  not  lobate, 
the  ribs  double. 

Tail)  suborbicular,  not  so  large  as  the  buckler,  co- 
vered with  an  epidermis. 

This  genus  derives  its  name  from  two  Greek  words, 
which  signify  double  ribsj  many  of  the  trilobites  are 
thus  characterized;  but  in  no  species,  is  this  organi- 
zation so  remarkable  as  in  those  which  belong  to  the 
Genus  Dipleura.  The  expansion  of  the  tail  resem- 
bles, in  some  degree,  that  of  the  Isotelus,  but  other 
obvious  characters  sufficiently  distinguish  it  from 
that  interesting  genus.  The  fossils  arranged  under 
this  section  are  larger  than  most  other  trilobites. 


79 

DIPLEURA  DEKAYI.     Green.      Casts  No.  30,  31,  and 
Figs.  8  &  9. 

Clypeo  lunato  punctate;  abdomine  quatuordecim 
articulis  duplicibus  vix  lobatis;  cauda  suborbiculari; 
limbo  lato  convexo  integerrimo;  oculis  oblique  de- 
flexis. 

The  buckler  is  subtriangular,  and  covered  with 
granulations;  the  anterior  portion  of  our  specimen 
being  mutilated,  we  cannot  determine  its  form  exactly. 
The  cheeks  are  very  prominent,  and  swell  up  gradually 
towards  the  oculiferous  protuberances,  which  are  ob- 
lique, and  marked  at  their  apex  with  a  depression, 
so  as  to  give  them  an  annular  appearance.  The  abdo- 
men is  crossed  by  fourteen  double  distinct  articula- 
tions, not  interrupted  in  their  course,  by  the  two 
longitudinal  furrows,  so  common  in  most  of  the  tri- 
lobites;  but  owing  to  certain  curves  or  irregularities 
in  the  ribs  near  their  lateral  termination,  a  trilobate 
appearance  may  in  some  specimens  be  detected. 
Tail  suborbicular,  convex,  and  covered  with  a  thick 
epidermis. 

The  specific  name  of  this  species  was  given  in  com- 
pliment to  Dr.  James  E.  Qekay,  of  New  York,  whose 
valuable  paper  on  the  genus  Isotelus,  first  directed 
my  attention  to  the  American  trilobites. 

The  D.  Dekayi  has  been  found  in  several  districts 
of  the  United  States;  at  Lockport  in  the  State  of 
New  York,  it  is  not  uncommon.  The  small  speci- 
men from  which  our  cast  of  the  abdomen  and  caudal 


80 

end  was  taken,  is  in  the  fine  cabinet  of  Mr.  William 
Hyde,  who  permitted  me  to  use  it  with  his  wonted 
liberality  and  kindness.  It  is  said  to  have  been  found 
in  Northumberland,  Pennsylvania,  and  occurs  in  grey 
carbonate  of  lime.  In  the  Philadelphia  Museum, 
there  is  a  fine  fragment  of  this  species,  in  which  there 
is  embedded  some  crystals  of  iron  pyrites;  it  was  ob- 
tained in  Ulster  County,  New  York.  In  the  cabinet 
of  the  Academy  of  Natural  Sciences,  there  is  a  longi- 
tudinal and  hollow  fragment,  filled  with  ochre,  and 
the  oxide  of  iron;  it  is  labelled  from  Lockport,  New 
York.  At  Mount  Hope  Institution,  near  Baltimore, 
there  is  also  a  good  specimen  from  the  same  locality. 
In  the  Clinton  collection,  owned  by  the  Albany  Insti- 
tute, there  is  a  large  extended  fragment,  nearly  five 
inches  long.  It  is  embedded  in  brown  limestone, 
and  was  found  in  Madison  County,  N.  Y.  There  are 
twelve  articulations  of  the  abdomen  remaining,  and 
the  epidermal  covering  of  the  tail  is  distinctly  marked 
with  numerous  dots.  In  the  same  collection  there  is 
another  large  fragment  of  this  species,  consisting  of 
the  tail  and  fourteen  articulations,  It  was  found  in 
Steuben  County,  New  York;  and  occurs  in  grey 
limestone.  It  is  slightly  contracted  and  very  much 
depressed  laterally.  There  js  also  a  head  in  the  same 
kind  of  limestone,  from  Cazenovia,  Madison  County, 
New  York.  In  the  cabinet  of  the  Institute  there  is 
another  specimen  of  this  species,  about  six  inches 
in  length,  and  nearly  perfect;  it  is  also  embedded  in  a 
similar  rock,  and  was  brought  from  Rochester,  Mun- 
roe  County,  New  York. 


81 

The  original  of  the  head  from  which  our  cast  was 
made,  is  in  the  cabinet  of  P.  A.  Browne,  Esq.,  and 
was  found  by  that  enterprising  geologist  near  Le- 
highton,  Pa. 

GENIJS  TRIMERUS.*     Green. 

Body,  contractile,  tapering,  compressed. 

Buckler,  pustulous,  indistinctly  lobate,  with  only 
two  small  elevated  oculiferous  tubercles. 

•Abdomen,  with  thirteen  distinct,  double  articula- 
tions— divided  into  three  lobes  by  a  slight  longitudi- 
nal furrow. 

Flanks,  or  lateral  lobes,  not  so  broad  as  the  middle 
lobe. 

Tail,  tapering  to  an  obtuse  point,  pustulous,  and 
marked  with  ten  articulations. 

This  genu$  resembles  in  some  respects  both  the 
Calymene  and  Dipleura.  The  form  of  the  buckler, 
the  position  a'nd  structure  of  the  oculiferous  tuber- 
cles, and  the  scarcely  lobate  divisions  of  the  ab- 
domen, will  readily  distinguish  it  from  the  Caly- 
menes.  The  articulations  of  the  tail,  not  being 
covered  with  a  shelly  crust,  is  a  character  too  ob- 
vious to  confound  it  with  the  genus  Dipleura.  There 
is,  we  think,  a  beautiful  chain  of  gradations  of  resem- 
blances, between  the  Isotelus,  Dipleura,  Hemicryp- 
turus  and  Trimerus.  The  lobes  of  the  abdomen  of 
the  Isotelus  are  very  distinct,  and  the  articulations 
of  the  tail  are  hid  by  a  broad  thick  shelly  crust.  The 

From  the  Greek  for  "  three  divisions." 


82 

lobes  in  the  Dipleura  are  scarcely  apparent,  the 
ribs  more  numerous;  and  the  covering  of  the  tail 
much  smaller.  The  lobes  of  the  Hemicrypturus  are 
like  those  of  the  Isotelus;  but  the  lateral  ones  only 
of  the  tail  are  covered.  In  the  genus  Trimerus  the 
lobes  are  like  those  of  Dipleura,  but  the  articulations 
of  the  tail  are  exposed. 

TRIMERUS  DELPHINOCEPHALUS.    Green.    Cast  No.  32, 
and  Fig.  1. 

Clypeo  semilunari,  antice  compresso;  oculis  mi- 
nimis,  enimentissimis;  articulis  duplicibus  vix  lo- 
batis;  cauda  attenuata;  corpore  tuberculata. 

In  the  rich  cabinet  of  American  fossils  in  the 
Albany  Institute,  there  are  two  fine  specimens  of  this 
species,  and  I  am  indebted  to  that  rising  and  liberal 
institution,  for  the  use  of  them  in  the  present  work. 
Our  cast  is  made  from  the  smaller  and  more  perfect 
specimen  of  the  two.  The  outline  of  the  buckler 
forms  an  irregular  semi-ellipse.  The  front  is  convex 
between  the  eyes,  and  very  much  depressed  anterior- 
ly, so  as  to  form  a  sharp  edge.  The  posterior  part 
of  the  buckler  is  marked  with  a  transverse  groove 
parallel  with  the  articulations  of  the  back.  The 
cheeks  are  small  and  triangular;  the  small  elevated 
eye-shaped  tubercles  being  placed  in  the  middle, 
nearly  equidistant  from  each  of  the  angles.  The 
eyes  are  not  reticulated,  the  summit  of  each  tubercle 
only  presenting  a  plain  oval  foramen.  The  middle 


83 

lobe  of  the  abdomen  is  much  broader  than  the  lateral 
lobes,  and  has  13  distinct,  double  articulations.  The 
side  lobes  are  curved,  and  each  costal  arch  is  flatten- 
ed anteriorly  near  their  lower  extremities,  no  doubt 
for  the  purpose  of  enabling  the  animal  to  roll  itself 
into  a  ball.  The  tail  is  tapering,  and  is  composed  of 
ten  articulations.  The  crustaceous  covering  is  here 
more  thickly  deposited  than  on  any  other  part.  The 
entire  shell  seems  to  have  been  covered  with  minute 
elevated  dots;  these  are  beautifully  distinct  on  the 
buckler  and  on  the  tail.  Whole  length  of  the  speci- 
men described,  not  quite  two  inches. 

The  other  specimen  of  this  species  in  the  cabinet 
of  the  Albany  Institute,  is  a  large  caudal  end,  three 
inches  arid  a  half  long,  entirely  perfect.  Both  of 
these  fossils  were  brought  from  Williamsville,  Nia- 
gara county,  New  York.  They  occur  in  a  dark  shelly 
limestone,  filled  with  other  petrifactions.  The  cal- 
careous matter  which  has  mineralized  the  trilobite, 
in  this  instance,  as  in  most  others,  is  of  a  much  darker 
hue  than  the  surrounding  rock. 

GENUS  CERAURUS.     Green. 

Body,  very  much  depressed,  and  slightly  tapering. 

Buckler,  scarcely  trilobate;  cheeks  large,  flat,  with 
small  remote  oculiform  tubercles;  posterior  angle  of 
the  buckler  spinous. 

Abdomen,  with  twelve  articulations. 

Tail,  rounded  at  the  end,  but  terminating  on  each 
side  with  two  slightly  curved  spines. 


84 

The  name  of  this  genus  is  derived  from  the  remark- 
able spinous  projections  from  the  caudal  end;  this 
peculiar  organization  separates  it  widely  from  the 
other  genera.  The  Paradoxides  Spinulosus  of  Wah- 
lenberg,  which  is  supposed  to  be  the  old  Entomolithus 
Pamdoxus  of  Linne,  the  fossil,  with  which  all  the  tri- 
lobites  were  for  a  long  time  confounded,  has  not 
only  projecting  spines  from  the  tail,  but  from  all  the 
costal  arches  of  the  lateral  lobes.  The  presence  of 
eyes  or  of  oculiferous  tubercles  in  the  Ceraurus,  would 
alone  be  sufficient  to  separate  .it  from  the  genus  to 
which  that  interesting  fossil  belongs.  In  the  eighth 
volume  of  Annales  des  Sciences  Naturelles,  Count 
Rasoumowsky  has  figured  and  described  the  frag- 
ment of  a  very  curious  relic,  which  seems  to  be  an 
intermediate  link  between  our  genus  and  paradox- 
ides;  in  addition  to  a  number  of  filamentous  elonga- 
tions of  the  costal  arches,  a  curved  spine  seems  to 
project  from  the  end  of  the  tail,  as  in  the  «#.  limulurus. 
No  name  is  given  to  this  trilobite,  which  appears  to 
have  been  found  on  the  banks  of  the  Yaousa,  near 
Moscow,  where  it  occurs  in  black,  coarse,  argillaceous 
schistus.  The  Ceraurus  is  probably  a  very  rare  ani- 
mal remain,  as  we  have  only  met  with  it,  in  the  unri- 
valled cabinet  of  trilobites  belonging  to  the  Albany 
Institute. 

CERAURUS  PLEUREXANTHEMUS.    Green.     Cast  No.  33. 
Fig.  10. 

Clypeo  postice  arcuato,  angulo  externo  in  mucro- 
nem  valde  producto;  oculis  minimis  remotis,  post- 


85 

abdomine  in  spinam  arcuatam  acutam  utrinque  ex- 
tenso. 

The  exact  contour  of  this  species  cannot  be  per- 
fectly ascertained  from  our  specimen;  it  seems,  how- 
ever, to  have  been  lunate.  The  horns  of  the  crescent 
which  form  the  posterior  angles,  are  very  distinct, 
and  they  project  like  curved  spines,  some  distance  on 
each  side  of  the  head.  The  middle  lobe  or  front  is 
faintly  scalloped  on  each  side  along  the  cheeks.  The 
cheeks  are  rather  large,  and  are  furnished  with  two 
small  oculiform  tubercles,  very  remote  from  each  other, 
and  quite  near  to  the  anterior  portion  of  the  buckler. 
The  abdomen  is  composed  of  twelve  articulations. 
The  lateral  lobes  of  the  abdomen  are  flat,  and  each  of 
the  ribs,  at  about  half  their  extent,  is  marked  on  the 
upper  surface,  with  an  elevated  pimple.  These  little 
pustules  are  nearly  on  a  line  with  the  oculiferous  tu- 
bercles of  the  buckler,  and  present  two  parallel  ranges 
down  the  body,  one  on  each  side  of  the  middle  lobe, 
and  are  terminated  by  a  curved  spine,  which  projects 
to  some  distance  beyond  the  tail  of  the  animal. 
Length  one  inch  and  a  fourth. 

This  remarkable  organic  relic  was  found  near 
Newport,  in  the  State  of  New  York.  It  is  embedded 
in  black  limestone  shale,  and  so  exceedingly  depress- 
ed is  this  animal,  that  a  very  thin  lamen  of  the  slate 
removed  from  the  surface  would  destroy  every  ves- 
tige of  its  appearance.  I  am  indebted  to  my  early 
friend,  Professor  T.  R.  Beck,  for  the  use  of  this  valu- 
able petrifaction,  which  now  belongs  to  the  cabinet 
of  the  Albany  Institute. 


86 

GENUS  TRIARTHRUS.     Green. 

Body,  slightly  convex;  contractile? 

Buckler? 

Abdomen,  with  three  articulations,  side  lobes  longi- 
tudinal, narrow,  and  wedge-shaped. 

Tail,  broad,  rounded,  without  any  membranaceous 
expansion. 

The  name  of  this  genus  is  derived  from  the  cir- 
cumstance, that  the  abdomen  has  but  three  articula- 
tions; an  organization  which  is  very  peculiar.  These 
curious  fossil  animals  are  very  abundant  in  the  rocks 
in  which  they  are  found;  but  though  I  have  examined 
a  multitude  of  specimens  from  different  localities,  no 
vestige  of  the  head  or  buckler  could,  on  the  most  mi- 
nute examination,  be  discovered.  Whether  these  ani- 
mals, during  their  petrifaction,  were  so  contorted  or 
rolled  up,  as  to  bring  the  extremities  of  the  body  to- 
gether, in  such  a  manner  as  to  present  the  posterior 
folded  part  only  to  the  view;  or  whether  the  buckler 
has  been  destroyed  by  the  process  of  mineralization, 
as  appears  frequently  to  happen  with  the  asaphs,  we 
are  at  a  loss  to  determine. 

The  animal  remains  which  belong  to  the  genus 
Triarthrus,  differ  so  much  in  their' form  and  general 
characters  from  all  the  other  trilobites,thatwe  perhaps 
ought  to  regard  them  as  forming  another  race  of  be- 
ings. They  are,  however,  more  nearly  allied  to  this 
family  than  the  Agnosti  of  Professor  Brongniart. 


87 

TRIARTHRUS  BECKII.     Green.     Cast  No.  34.  Fig.  6. 

Cauda  subrotunda,  bipunctata;  articulis  abdominis 
tribus,  absque  lobis  lateralibus  consuetis,  sed  lobo 
arcuato  utrinque  apposite. 

The  only  portions  of  this  fossil  which  have  yet  been 
found,  are  the  abdomen  and  tail.  The  abdomen  is 
composed  of  three  joints;  the  first  passes  from  the 
side  lobes  completely  over  the  body,  and  on  its  upper 
surface,  near  the  middle  of  the  back,  there  is  often  a 
minute  elevated  pimple.  The  other  two,  pass  ob- 
liquely from  the  lateral  lobes,  and  are  interrupted  in 
their  course  over  the  body.  The  tail,  or  posterior 
portion,  is  expanded,  something  like  that  of  the  Iso- 
telus  or  Dipleura,  and  has  a  deep  puncture  on  each 
side,  about  half  the  distance  between  its  terminal 
border  and  the  last  articulation  of  the  abdomen.  The 
lateral  lobes  are  unlike  those  of  any  other  genus. 
They  form  narrow  cuniform  appendages  to  the  sides; 
near  the  first  joint  of  the  abdomen  they  are  crossed 
transversely  by  an  elevated  ridge,  from  which  they 
gradually  taper  along  the  sides  of  the  body,  and  ap- 
pear to  inosculate  in  a  delicate  point  at  the  central 
border  of  the  tail.  The  abdominal  articulations  do 
not  pass  over  these  lobes,  but  just  below  the  last 
joint,  a  little  transverse  furrow,  in  perfect  specimens, 
may  be  noticed.  The  largest  specimen  of  this  frag- 
ment I  have  seen  is  exactly  half  an  inch  in  length. 
This  fossil  occurs  in  black  shaly  limestone,  on  the 


canal  near  Cahooes  Falls,  in  the  State  of  New  York, 
and  at  a  number  of  other  places  in  that  State. 

I  have  named  this  species  in  compliment  to  my 
early  friend,  Professor  Theodore  Romeyn  Beck,  M.  D. 
well  known  both  at  home  and  abroad,  as  the  learn- 
ed author  of  the  work  on  Medical  Jurisprudence. 
Some  time  after  commencing  this  little  Monograph, 
I  communicated  my  plan  to  Dr.  Beck,  and  was  sur- 
prised and  gratified  to  find  that  he  was  also  engaged 
with  the  same  inquiries,  and  that  he  was  then  busy 
in  arranging  and  examining  the  unique  collection  of 
trilobites  belonging  to  the  Albany  Institute.  With- 
out the  smallest  hesitation,  he  placed  all  his  speci- 
mens at  my  disposal,  and  has  facilitated  otherwise 
my  undertaking,  by  every  means  in  his  power. 
• 

GENUS  NUTTAINIA.    Eaton. 

Professor  A.  Eaton,  in  his  Geological  Text  Book, 
has  proposed  the  Genus  Nuttainia,  to  include  two 
remarkable  trilobites  which  could  not  properly  be 
arranged  in  any  of  the  previously  established  genera. 
The  two  fossils  here  grouped  together,  bear  no  gene- 
ric relation  to  each  other.  The  first  species  which 
he  calls  N.  Concentrica,  belongs  to  the  genus  Crypto- 
lythus,  which  was  proposed  before  the  appearance  of 
his  work,  and  has  therefore  been  noticed  in  another 
place. 

The  genus  Nuttainia  is  thus  characterized  by  its 
author:  "  Head  in  three  lobes,  the  middle  one  most 
prominent ;  the  two  lateral  lobes  sub-hemispherical, 


89 

or  sub-quadrantalj  the  whole  head  bordered  anterior- 
ly with  a  punctured  fillet:  body  distinctly  three  lobed, 
middle  lobe  sub-cylindric,  and  not  so  broad  as  the 

side  lobes." 

* 

NUTTAINIA  SPARSA.    Eaton.     Cast  No.  35. 

Fillet  nearly  straight  in  front  of  the  middle  lobe  of 
the  head,  punctures  of  the  fillet  scattered  irregularly, 
without  any  alternating  ridgesj  head  compressed,  co- 
vered with  scattered  punctures,  having  its  side  lobes 
much  smaller  than  the  middle  one;  middle  lobe  with 
straight  sides,  giving  it  somewhat  the  form  of  a  pa- 
rallelogram. 

Found  in  third  grauwacke,*  or  grit  slate  in  Coey- 
mans,  sixteen  miles  south-west  of  Albany.  I  have 
the  head  of  one  before  me  two  and  a  half  inches 
broad,  and  one  and  a  half  long.  The  whole  of  the 
animal  must  have  been  six  or  seven  inches  in  length. 

The  above  account  is  copied  from  the  "  Text 
Book."  Mr.  Eaton  was  kind  enough  to  lend  me  the 
only  specimen  of  this  curious  fossil  remain,  which 
has  yet  been  found;  from  which  his  description  was 
taken,  and  of  which  our  cast  is  an  exact  copy.  His 
generic  characters  do  not  in  our  opinion  at  all  ap- 
ply to  this  fragment.  Nothing  but  the  head  of  this 

*  In  a  manuscript  note,  Professor  Eaton  states  that  the  third 
grauwacke,  or  grit  slate  of  Coeymans,  "  alternates  with  the  un- 
derlaying cherty  lime  rock."  This  opinion  some  of  our  geologi- 
cal friends,  familiar  with  the  formation  at  Coeymans,  and  with 
the  Professor's  nomenclature  of  rocks,  have  called  in  question. 
H  2 


90 

singular  trilobite  remains,  and  it  is  doubtful  whether 
what  is  said  to  be  the  punctured  fillet,  "  nearly 
straight  in  front  of  the  middle  lobe,"  be  not  the  com- 
mencement of  the  articulations  of  the  abdomen.  The 
whole  fragment  looks  very  much  like  the  head  of 
some  large  Asaph  or  Ogygia. 

GENUS  BRONGNIATIA.     Eaton. 

Professor  Eaton  has  proposed  the  name  Brongnia- 
tia  (Brongniartia?)  for  a  genus  of  trilobites,  which 
we  think  he  has  not  defined  with  sufficient  accuracy 
to  be  of  any  practical  use.  The  Isotelus  gigas  of 
Dr.  Dekay,  which  has  been  for  a  long  time  so  well 
established,  is  here  ranked  merely  as  a  species  under 
the  name  of  B.  isotela.  The  relic  which  we  described 
before  the  Geological  Text  Book  appeared  as  the 
Triarthrus  JBeckii,  forms  the  species  B.  carcinoclea — 
and  the  trilobite  which  is  supposed  to  be  the  Asaphus 
platycephalus  of  Stokes,  is  the  only  other  species 
mentioned.  The  A.  platycephalus,*  we  know  to  be 
identical  with  the  I.  gigas,  and  as  the  animal  remain 
described  by  Mr.  Eaton  is  entirely  different  from  Dr. 
Dekay's  fine  species,  we  subjoin  the  account  given  in 
the  "  Text  Book." 

Genus  Brongniatia — Fore  abdomen  always,  and 
post  abdomen  in  some  cases,  longitudinally  divided 
into  three  lobes,  by  regular  series  of  undulations  tra- 

*  For  a  figure  and  description  of  the  Asaphus  Platycephalus, 
by  Mr.  Stokes,  see  Transactions  of  the  Geological  Society.  Se- 
cond Series,  vol.  i. 


91 

versing  the  joints,  without  grooves;  articulations  of 
the  side  lobes  being  manifest  continuations  of  those  of 
the  middle  lobe,  and  consequently,  agreeing  in  num- 
ber. 

BRONGNIATIA  PLATYCEPHALA.     Eaton. 

Head  and  fore  abdomen  very  broad  and  depressed, 
the  abdomen  with  ten  joints  curved  forwards  at  the 
undulations;  post  abdomen  and  tail  with  about  fif- 
teen joints  curved  backwards  at  the  undulations;  the 
three  lobes  of  the  tail  more  distinctly  separated;  divi- 
sions between  the  joints  of  the  abdomen  double. 

The  representation  of  B.  platicephala,  figure  20, 
plate  2,  of  the  Geological  Text  Book,  if  it  be  accu- 
rately drawn,  is  certainly  of  a  trilobite  never  before 
described.  On  the  buckler,  which  is  without  eyes, 
there  is  delineated  a  figure,  not  unlike  some  of  the 
leaves  of  the  mulberry  tree. 

The  tail  is  also  very  peculiar.  In  Silliman's  Jour- 
nal, Volume  21st,  page  136,  Professor  Eaton  pro- 
posed for  this  curious  fossil  the  temporary  name  of 
Ogygies  latissimus.  "It  is  found,  he  observes,  in  the 
upper  soft  slaty  variety  of  the  rock  which  has  been 
so  successfully  used  for  the  lias  cement  at  Chitteningo, 
Sec.  Dr  Smith,  of  Lockport,  (N.  Y.)  sent  me  two 
specimens,  taken  from  a  continuation  of  the  Chitten- 
ingo  lias  rock,  immediately  beneath  the  geodiferous 
lime  rock  on  which  the  cherty  (cornitiferous)  re- 
poses." The  whole  animal  is  six  inches  long,  and 
three  broad. 


92 


NATURE  OF  THE  TRILOBITE. 

Every  one  familiar  with  the  history  of  the  Trilo- 
bites,  is  aware  that  a  good  deal  of  controversy  has 
existed  among  naturalists,  respecting  the  precise 
link  in  the  grand  chain  of  organized  beings,  these  sin- 
gular fossil  animals,  should  occupy.  Professor  Brong- 
niart,  Dr.  Dekay,  Audouin,  and  several  other  acute 
observers,  have  placed  them  in  the  vicinity  of  the  Li- 
muli,  and  other  Entomostraca  with  numerous  feet; 
while  P.  A.  Latreille  and  others,  presuming  that  these 
animals  were  destitute  of  locomotive  organs,  as  no 
vestige  of  them  has  ever  been  discovered,  fix  their 
natural  position  in  the  neighbourhood  of  the  Chi- 
tonesj  or  rather  that  they  constituted  the  original 
stock  of  the  Articulata,  being  connected  on  the  one 
hand  with  these  latter  Mollusca,  and  on  the  other 
with  those  first  mentioned,  and  even  with  the  Glome- 
ris.*  It  was  our  original  intention  to  have  closed 
this  Monograph  with  a  short  history  of  these  theories 
— and  of  the  notion  advanced  by  Latreille  and  others, 
that  the  Trilobites  have  been  annihilated  by  some 
ancient  revolution  of  our  planet,  All  these  matters, 
we  think,  are  now  put  to  rest  by  the  late  discovery 
of  some  living  Trilobites  in  the  southern  seas,  near 
the  Falkland  Islands.  In  the  cabinet  of  the  Albany 
Institute,  we  have  examined  some  of  these  recent 
animals,  which  have  very  nearly  the  size  and  general 

*  See  Cuvier's  Animal  Kingdom,  vol.  iii.  pp.  135—6. 


93 

appearance  of  the  Paradoxides  Boltoni,  as  represented 
on  our  frontispiece^  the  species  cannot,  however,  be- 
long to  that  genus,  as  the  buckler  is  furnished  with  eyes 
very  similar  to  those  of  the  Calymene  Bufo;  its  organs 
of  locomotion  are  short,  numerous,  and  concealed  un- 
der the  shell — but  I  do  not  feel  at  liberty  to  notice 
the  interesting  animal  more  minutely.  It  will  pro- 
bably be  described  and  figured  shortly,  in  a  perfectly 
full  and  satisfactory  manner,  by  Dr.  James  Eights, 
the  enterprising  discoverer,  together  with  several 
other  new  and  remarkable  genera  and  species  belong- 
ing to  the  Entomostraca. 


FINIS. 


to  tfie  &pec(r& 


CALYMENE  Blumenbachii,      - 

Callicephala, 

Selenecephala, 

Platys, 

Microps 

Anehiops, 

Diops, 

Macrophthalma     - 

Bufo, 

Rana, 
ASAPHUS,    Laticostatus, 

Selenurus, 

Limulurus, 

Caudatus, 

Hausmanni 

Pleuroptyx, 

Micrurus, 

Wetherilli,  r 

PARADOXIDES  Boltoni, 
OGYGIA         Sillimani, 
ISOTELUS    Gigas, 

Planus, 

Cyclops, 

Megalops, 

Stegops, 
CRYPTOLITHUS  Tessellatus, 

Bigssbii, 

DIPLEURA    Dekayi, 
TRIMERUS  Delphinocephalus, 
CERAURUS  Pleurexanthemus, 
TRIARTHRUS  Beckii, 
NUTTAINIA  Sparsa, 
BRONGNIATIA  PJatycephala, 


JOSEPH  BRAND, 

No.  12,  CASTLE  STREET,  PHILADELPHIA, 

Teacher  of  the  Art  of  Preparing  Birds,  Quadrupeds, 
Reptiles,  $c.  4»c. 

AND  OF  THE 

Art  of  making  Moulds  and  Casts  in  Wax,  Plaster, 
and  Compositions. 

In  addition  to  the  casts  taken  from  the  originals  of  the  Trilo- 
bites,  he  has  also  a  few  fine  casts  of  the  bones  of  the  Megalonix 
Laqueatus,  Harlan. — Scaphites  Cuvieri,  Morton. — Mosasauru3 
tooth,  and  of  several  rare  fossil  American  Plants; — all  taken  from 
the  original  fossils,  in  the  Cabinet  of  the  Academy  of  Natural 
Sciences,  &c.  &c.  These  models  are  fac  similes  of  the  real  ob- 
jects, coloured  according  to  nature. 

As  the  originals  of  the  above  are  in  the  possession  of  different 
public  and  private  cabinets  throughout  the  United  States,  I  have 
at  great  trouble  and  expense,  taken  from  them  exact  patterns, 
so  as  to  accommodate  museums  and  scientific  gentlemen  with 
them  on  very  reasonable  terms.  This  practice  is  now  used  in 
several  parts  of  Europe ;  and  thus  the  curious  are  able  to  supply 
their  cabinets  with  rare  specimens,  often  superior  to  the  origi- 
nals. 


JOSEPH  BRANO  having  finished  for  us  a  number  of  models 
of  different  objects  in  Natural  History,  we  have  no  hesitation  in 
recommending  him  as  an  exceedingly  skilful  artist. 

JACOB  GREEN,  M.  D. 

RICH'D.  HARLAN,  M.  D. 

P.  A.  BROWNE,  ESQ. 

CHAS.  A.  POULSON. 

ISAAC  PARRISH,  M.  D. 

S.  G.  MORTON,  M.  D. 
Philadelphia,  October  3d,  1832. 


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